Proceedings of the Royal Society B: Biological Sciences
Killing is often an unavoidable and necessary procedure for laboratory mice involved in scientifi... more Killing is often an unavoidable and necessary procedure for laboratory mice involved in scientific research, and providing a humane death is vital for public acceptance. Exposure to carbon dioxide (CO 2 ) gas is the most widely used methodology despite well proven welfare concerns. Consequently, the continued use of CO 2 and its globally permitted status in legislation and guidelines presents an ethical dilemma for users. We investigated whether killing with hypobaric hypoxia via gradual decompression was associated with better welfare outcomes for killing laboratory mice. We compared the spontaneous behaviour of mice exposed to CO 2 , decompression or sham conditions, and used analgesic or anxiolytic interventions to determine their relative welfare impact. Gradual decompression resulted in longer times to unconsciousness and death and the pharmacological interventions support the notion of a minimally negative animal experience, while providing further evidence for pain and anxiet...
Abstract 1. The paper explains the use and method of operation of electrical water bath stunners,... more Abstract 1. The paper explains the use and method of operation of electrical water bath stunners, and explains the possible current pathways through a single bird and through a number of birds. 2. A mathematical model has been formulated to demonstrate the effects of bird resistance and physical attitude of the bird on the current received by individual birds in a water bath stunner. 3. The model shows that readings from ammeters installed in series with commercial stunners, or the values shown on voltmeters, are not an accurate indicator or a guarantee that individual birds are effectively stunned. 4. The model demonstrates the need for a stunner to supply a constant current to each bird, rather than operate at a constant voltage where the current which the bird receives is dependant upon its own resistance.
This pilot experiment was conducted to ascertain whether CO2-enriched high expansion foam could b... more This pilot experiment was conducted to ascertain whether CO2-enriched high expansion foam could be an acceptable and efficient alternative in emergency killing of poultry. This method could have wide-ranging applications but with particular emphasis on small (backyard) flocks, free-range sheds or open (naturally-ventilated) housings. The objectives of the study were as follows: 1) to determine whether the injection of foam and being covered with foam leads to fear or panic reactions in birds; 2) to determine the time taken to render birds unconscious and dead and 3) to determine whether any pathological abnormalities are observed post mortem. Six laying hens were individually exposed to increasing levels of CO2 foam with an expansion rate of 300:1. The test box containing individual birds filled with foam within 30 s. During foaming, two out of six birds tried to escape from the test box (1–2 attempts per bird). Apart from displaying greater alertness, birds showed no aversive react...
this exercise, participants may be given a hand drawn map of a farm and asked to indicate the zon... more this exercise, participants may be given a hand drawn map of a farm and asked to indicate the zoning using colored markers. In either case, they are asked to discuss their logic and sequence. Poultopia is a contained set of scenarios and maps where all resources (human and equipment, represented on stickers) are available for a HPAI outbreak response. In a series of iterations, participants must determine where surveillance should occur; where road blocks should be placed during an outbreak; which birds to cull first; what type of people (for example: veterinarian, medical, police, decontamination specialist) and equipment are needed during the outbreak response; and the time required and thus how many people of each type are needed. The Poultopia scenarios presented are adapted to the conditions of the region where the training takes place, thus adding to its realism and utility.
During outbreaks of notifiable diseases in poultry measures are taken to restrict the spread of t... more During outbreaks of notifiable diseases in poultry measures are taken to restrict the spread of the disease. Mass on-farm killing of birds using gasfilled foam is such a measure. This study examines the method and technologies involved using gas-filled foam and looks at the problems involved by scaling up the procedure. Methods and results are discussed in relation to poultry physiology and behaviour monitored during controlled studies. Recommendations are made for system design and an operational protocol is provided for practical on-farm implementation.
1. Four mechanical poultry killing devices; modified Armadillo (MARM), modified Rabbit Zinger (MZ... more 1. Four mechanical poultry killing devices; modified Armadillo (MARM), modified Rabbit Zinger (MZIN), modified pliers (MPLI) and a novel mechanical cervical dislocation gloved device (NMCD), were assessed for their killing potential in the cadavers of euthanised birds of 4 type/age combinations: layer/adult, layer/pullet, broiler/slaughter-age and broiler/chick. 2. A 4x4x4 factorial design (batch x device x bird type + age) was employed. Ten bird cadavers per bird type and age were tested with each of the 4 devices (N = 160 birds). All cadavers were examined post-mortem to establish the anatomical damage caused by each device. 3. Three of the mechanical methods: NMCD, MARM and MZIN demonstrated killing potential, as well as consistency in their anatomical effects, with device success rates of over 50% indicating that the devices performed optimally more than half of the time. NMCD had the highest killing potential, with 100% of birds sustaining the required physical trauma to have caused rapid death. 4. The MPLI was inconsistent, and only performed optimally for 27.5% of birds, despite good killing potential when performing well. Severe crushing injury was seen in >50% of MPLI birds, suggesting that birds would die of asphyxia rather than cerebral ischaemia, a major welfare concern. As a result, the modified pliers are not recommended as a humane onfarm killing device for chickens. 5. This experiment provides important data on the killing potential of untried novel percussive and mechanical cervical dislocation methods, informing future studies.
An alternative emergency method for killing poultry on-farm is required following European legisl... more An alternative emergency method for killing poultry on-farm is required following European legislation changes (EU 1099/2009), which heavily restricts the use of manual cervical dislocation. This study investigated the kill efficacy of two mechanical methods that conform to the new legislation: (1) a novel mechanical cervical dislocation device; and (2) a modified captive bolt device (Rabbit Zinger TM) and manual cervical dislocation (the control). Killing treatments were applied to broilers and layers at two stages of production (broilers: 2-3 weeks 2 and 5 weeks of age; layers: 12-13 weeks and 58-62 weeks), with a total of 180 birds. Latency to abolition of cranial and behavioural reflexes, as well as post-mortem analysis of the physiological damage produced, were used to estimate time to unconsciousness and assess kill efficacy. The novel mechanical cervical dislocation device was reliable and a practical method for killing poultry on-farm, with 100% kill success (F 2,167 = 19.96 , P < 0.001) and cranial reflex interval mean durations lasting for 0.0-103.0 s post-kill (jaw tone (F 2,150 = 13.34 , P < 0.001); pupillary (F 2,150 = 101.66 , P < 0.001); nictitating membrane (F 2,150 = 1.61 , P = 0.191); and rhythmic breathing (F 2,150 = 1.46 , P = 0.235) compared to the modified Rabbit Zinger TM (72% kill success rate, 0.3-124.9 s cranial reflex mean durations) and manual cervical dislocation (100% kill success rate, 0.0-119.3 s cranial reflex mean durations). The novel mechanical cervical dislocation device resulted in consistent anatomical damage to the birds (e.g. high dislocation of the neck and severing of the spinal cord) compared to the manual method, despite both having 100% success rate, while the modified Rabbit Zinger TM was difficult to operate and resulted in varied anatomical damage. The novel mechanical cervical dislocation device showed promise as a replacement kill method on farm for poultry.
This review examines methods for culling small numbers of poultry on farm, considering both commo... more This review examines methods for culling small numbers of poultry on farm, considering both common techniques and methods that are yet to be tested on poultry. The aim of this review is to inform the design of experiments that will assess the pros and cons of culling techniques. The methods reviewed include manual and mechanical cervical dislocation, crushing methods (such as burdizzos or pliers), percussive devices, blunt force trauma and a brain-stem piercing device. Previous work on these approaches, of which there is a limited dataset, has relied on behavioural and brain activity as proxy measures of unconsciousness (insensibility) and death, however there remains some uncertainty as to when birds can be considered unequivocally insensible. These factors will be considered when deciding which of the methods will be recommended to be taken forward for further assessment.
This pilot experiment was conducted to ascertain whether CO2-enriched high expansion foam could b... more This pilot experiment was conducted to ascertain whether CO2-enriched high expansion foam could be an acceptable and efficient alternative in emergency killing of poultry. This method could have wide-ranging applications but with particular emphasis on small (backyard) flocks, free-range sheds or open (naturally-ventilated) housings. The objectives of the study were as follows: 1) to determine whether the injection of foam
The slaughter of poultry differs from the slaughter of all other meat-producing animals in that t... more The slaughter of poultry differs from the slaughter of all other meat-producing animals in that the live birds are hung upside down in shackles prior to slaughter. There is concern from animal welfare organizations such as the United Kingdom Farm Animal Welfare Council that this practice, although necessary for present methods of humane slaughter, causes possible distress and pain to the birds. This paper reviews the regulations on the provision for the welfare of poultry at slaughter as it affects shackling, the equipment involved in shackling, and the physiological and psychological effect of shackling on birds.
The effectiveness of current electrical stunning systems for pigs is discussed and the need for i... more The effectiveness of current electrical stunning systems for pigs is discussed and the need for improvements in the design and construction of stunning tongs and electrodes are explored. A review of existing stunning tong electrodes for use with free standing or restrained pig is discussed. The potential problems with existing systems are highlighted as: (1) the profile of the pigs head precludes the application of existing electrodes in the correct position; (2) the small area of contact enhances carbon build-up which increases electrical impedance; (3) the electrodes are easily tarnished with few cleaning tools provided. Good tong positions that span the brain are described as between the eye and ear on each side of the head, below the ear on each side of the head or, diagonal application between the top and bottom of the head. The notional contact impedance is the major component of resistance to current JYOW within the stunning system. The proposed use of dtyerent electrode designs and constructional material is investigated. The effect of the introduction of the fail-safe device would be to heighten the interest in contact impedance within the plant and that could ensure that the investigation of dtrerent electrodes is explored at least at plant level.
Disease control measures require poultry to be killed on farms to minimize the risk of disease be... more Disease control measures require poultry to be killed on farms to minimize the risk of disease being transmitted to other poultry and, in some cases, to protect public health. We assessed the welfare implications for poultry of the use of high-expansion gas-filled foam as a potentially humane, emergency killing method. In laboratory trials, broiler chickens, adult laying hens, ducks, and turkeys were exposed to air-, N 2-, or CO 2-filled high expansion foam (expansion ratio 300:1) under standardized conditions. Birds were equipped with sensors to measure cardiac and brain activity, and measurements of oxygen concentration in the foam were carried out. Initial behavioral responses to foam were not pronounced but included headshakes and brief bouts of wing flapping. Both N 2-and CO 2filled foam rapidly induced ataxia/loss of posture and vigorous wing flapping in all species, characteristic of anoxic death. Immersion in air-filled, high expansion foam had little effect on physiology or behavior. Physi
Proceedings of the Royal Society B: Biological Sciences
Killing is often an unavoidable and necessary procedure for laboratory mice involved in scientifi... more Killing is often an unavoidable and necessary procedure for laboratory mice involved in scientific research, and providing a humane death is vital for public acceptance. Exposure to carbon dioxide (CO 2 ) gas is the most widely used methodology despite well proven welfare concerns. Consequently, the continued use of CO 2 and its globally permitted status in legislation and guidelines presents an ethical dilemma for users. We investigated whether killing with hypobaric hypoxia via gradual decompression was associated with better welfare outcomes for killing laboratory mice. We compared the spontaneous behaviour of mice exposed to CO 2 , decompression or sham conditions, and used analgesic or anxiolytic interventions to determine their relative welfare impact. Gradual decompression resulted in longer times to unconsciousness and death and the pharmacological interventions support the notion of a minimally negative animal experience, while providing further evidence for pain and anxiet...
Abstract 1. The paper explains the use and method of operation of electrical water bath stunners,... more Abstract 1. The paper explains the use and method of operation of electrical water bath stunners, and explains the possible current pathways through a single bird and through a number of birds. 2. A mathematical model has been formulated to demonstrate the effects of bird resistance and physical attitude of the bird on the current received by individual birds in a water bath stunner. 3. The model shows that readings from ammeters installed in series with commercial stunners, or the values shown on voltmeters, are not an accurate indicator or a guarantee that individual birds are effectively stunned. 4. The model demonstrates the need for a stunner to supply a constant current to each bird, rather than operate at a constant voltage where the current which the bird receives is dependant upon its own resistance.
This pilot experiment was conducted to ascertain whether CO2-enriched high expansion foam could b... more This pilot experiment was conducted to ascertain whether CO2-enriched high expansion foam could be an acceptable and efficient alternative in emergency killing of poultry. This method could have wide-ranging applications but with particular emphasis on small (backyard) flocks, free-range sheds or open (naturally-ventilated) housings. The objectives of the study were as follows: 1) to determine whether the injection of foam and being covered with foam leads to fear or panic reactions in birds; 2) to determine the time taken to render birds unconscious and dead and 3) to determine whether any pathological abnormalities are observed post mortem. Six laying hens were individually exposed to increasing levels of CO2 foam with an expansion rate of 300:1. The test box containing individual birds filled with foam within 30 s. During foaming, two out of six birds tried to escape from the test box (1–2 attempts per bird). Apart from displaying greater alertness, birds showed no aversive react...
this exercise, participants may be given a hand drawn map of a farm and asked to indicate the zon... more this exercise, participants may be given a hand drawn map of a farm and asked to indicate the zoning using colored markers. In either case, they are asked to discuss their logic and sequence. Poultopia is a contained set of scenarios and maps where all resources (human and equipment, represented on stickers) are available for a HPAI outbreak response. In a series of iterations, participants must determine where surveillance should occur; where road blocks should be placed during an outbreak; which birds to cull first; what type of people (for example: veterinarian, medical, police, decontamination specialist) and equipment are needed during the outbreak response; and the time required and thus how many people of each type are needed. The Poultopia scenarios presented are adapted to the conditions of the region where the training takes place, thus adding to its realism and utility.
During outbreaks of notifiable diseases in poultry measures are taken to restrict the spread of t... more During outbreaks of notifiable diseases in poultry measures are taken to restrict the spread of the disease. Mass on-farm killing of birds using gasfilled foam is such a measure. This study examines the method and technologies involved using gas-filled foam and looks at the problems involved by scaling up the procedure. Methods and results are discussed in relation to poultry physiology and behaviour monitored during controlled studies. Recommendations are made for system design and an operational protocol is provided for practical on-farm implementation.
1. Four mechanical poultry killing devices; modified Armadillo (MARM), modified Rabbit Zinger (MZ... more 1. Four mechanical poultry killing devices; modified Armadillo (MARM), modified Rabbit Zinger (MZIN), modified pliers (MPLI) and a novel mechanical cervical dislocation gloved device (NMCD), were assessed for their killing potential in the cadavers of euthanised birds of 4 type/age combinations: layer/adult, layer/pullet, broiler/slaughter-age and broiler/chick. 2. A 4x4x4 factorial design (batch x device x bird type + age) was employed. Ten bird cadavers per bird type and age were tested with each of the 4 devices (N = 160 birds). All cadavers were examined post-mortem to establish the anatomical damage caused by each device. 3. Three of the mechanical methods: NMCD, MARM and MZIN demonstrated killing potential, as well as consistency in their anatomical effects, with device success rates of over 50% indicating that the devices performed optimally more than half of the time. NMCD had the highest killing potential, with 100% of birds sustaining the required physical trauma to have caused rapid death. 4. The MPLI was inconsistent, and only performed optimally for 27.5% of birds, despite good killing potential when performing well. Severe crushing injury was seen in >50% of MPLI birds, suggesting that birds would die of asphyxia rather than cerebral ischaemia, a major welfare concern. As a result, the modified pliers are not recommended as a humane onfarm killing device for chickens. 5. This experiment provides important data on the killing potential of untried novel percussive and mechanical cervical dislocation methods, informing future studies.
An alternative emergency method for killing poultry on-farm is required following European legisl... more An alternative emergency method for killing poultry on-farm is required following European legislation changes (EU 1099/2009), which heavily restricts the use of manual cervical dislocation. This study investigated the kill efficacy of two mechanical methods that conform to the new legislation: (1) a novel mechanical cervical dislocation device; and (2) a modified captive bolt device (Rabbit Zinger TM) and manual cervical dislocation (the control). Killing treatments were applied to broilers and layers at two stages of production (broilers: 2-3 weeks 2 and 5 weeks of age; layers: 12-13 weeks and 58-62 weeks), with a total of 180 birds. Latency to abolition of cranial and behavioural reflexes, as well as post-mortem analysis of the physiological damage produced, were used to estimate time to unconsciousness and assess kill efficacy. The novel mechanical cervical dislocation device was reliable and a practical method for killing poultry on-farm, with 100% kill success (F 2,167 = 19.96 , P < 0.001) and cranial reflex interval mean durations lasting for 0.0-103.0 s post-kill (jaw tone (F 2,150 = 13.34 , P < 0.001); pupillary (F 2,150 = 101.66 , P < 0.001); nictitating membrane (F 2,150 = 1.61 , P = 0.191); and rhythmic breathing (F 2,150 = 1.46 , P = 0.235) compared to the modified Rabbit Zinger TM (72% kill success rate, 0.3-124.9 s cranial reflex mean durations) and manual cervical dislocation (100% kill success rate, 0.0-119.3 s cranial reflex mean durations). The novel mechanical cervical dislocation device resulted in consistent anatomical damage to the birds (e.g. high dislocation of the neck and severing of the spinal cord) compared to the manual method, despite both having 100% success rate, while the modified Rabbit Zinger TM was difficult to operate and resulted in varied anatomical damage. The novel mechanical cervical dislocation device showed promise as a replacement kill method on farm for poultry.
This review examines methods for culling small numbers of poultry on farm, considering both commo... more This review examines methods for culling small numbers of poultry on farm, considering both common techniques and methods that are yet to be tested on poultry. The aim of this review is to inform the design of experiments that will assess the pros and cons of culling techniques. The methods reviewed include manual and mechanical cervical dislocation, crushing methods (such as burdizzos or pliers), percussive devices, blunt force trauma and a brain-stem piercing device. Previous work on these approaches, of which there is a limited dataset, has relied on behavioural and brain activity as proxy measures of unconsciousness (insensibility) and death, however there remains some uncertainty as to when birds can be considered unequivocally insensible. These factors will be considered when deciding which of the methods will be recommended to be taken forward for further assessment.
This pilot experiment was conducted to ascertain whether CO2-enriched high expansion foam could b... more This pilot experiment was conducted to ascertain whether CO2-enriched high expansion foam could be an acceptable and efficient alternative in emergency killing of poultry. This method could have wide-ranging applications but with particular emphasis on small (backyard) flocks, free-range sheds or open (naturally-ventilated) housings. The objectives of the study were as follows: 1) to determine whether the injection of foam
The slaughter of poultry differs from the slaughter of all other meat-producing animals in that t... more The slaughter of poultry differs from the slaughter of all other meat-producing animals in that the live birds are hung upside down in shackles prior to slaughter. There is concern from animal welfare organizations such as the United Kingdom Farm Animal Welfare Council that this practice, although necessary for present methods of humane slaughter, causes possible distress and pain to the birds. This paper reviews the regulations on the provision for the welfare of poultry at slaughter as it affects shackling, the equipment involved in shackling, and the physiological and psychological effect of shackling on birds.
The effectiveness of current electrical stunning systems for pigs is discussed and the need for i... more The effectiveness of current electrical stunning systems for pigs is discussed and the need for improvements in the design and construction of stunning tongs and electrodes are explored. A review of existing stunning tong electrodes for use with free standing or restrained pig is discussed. The potential problems with existing systems are highlighted as: (1) the profile of the pigs head precludes the application of existing electrodes in the correct position; (2) the small area of contact enhances carbon build-up which increases electrical impedance; (3) the electrodes are easily tarnished with few cleaning tools provided. Good tong positions that span the brain are described as between the eye and ear on each side of the head, below the ear on each side of the head or, diagonal application between the top and bottom of the head. The notional contact impedance is the major component of resistance to current JYOW within the stunning system. The proposed use of dtyerent electrode designs and constructional material is investigated. The effect of the introduction of the fail-safe device would be to heighten the interest in contact impedance within the plant and that could ensure that the investigation of dtrerent electrodes is explored at least at plant level.
Disease control measures require poultry to be killed on farms to minimize the risk of disease be... more Disease control measures require poultry to be killed on farms to minimize the risk of disease being transmitted to other poultry and, in some cases, to protect public health. We assessed the welfare implications for poultry of the use of high-expansion gas-filled foam as a potentially humane, emergency killing method. In laboratory trials, broiler chickens, adult laying hens, ducks, and turkeys were exposed to air-, N 2-, or CO 2-filled high expansion foam (expansion ratio 300:1) under standardized conditions. Birds were equipped with sensors to measure cardiac and brain activity, and measurements of oxygen concentration in the foam were carried out. Initial behavioral responses to foam were not pronounced but included headshakes and brief bouts of wing flapping. Both N 2-and CO 2filled foam rapidly induced ataxia/loss of posture and vigorous wing flapping in all species, characteristic of anoxic death. Immersion in air-filled, high expansion foam had little effect on physiology or behavior. Physi
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Papers by J. Sparrey