Laying Hen Welfare: Current Developments in Beak Trimming


(颜菲菲,江莎,Hengwei Cheng)

Beak trimming, removal of 1/3 to 1/2 of the beak, is a routine husbandry procedure practiced in the poultry industry to prevent feather pecking and cannibalism. Domestic chickens possess natural behavior and motivational systems inherited from their ancestors (Red Jungle fowls), such as dust bathing and foraging behavior-associated scratching and ground pecking. Prevention of chickens to perform those behaviors due to living environments results in stress, which leads to express harmful behaviors. Currently, there is no single housing system to meet all chicken’s behavioral and physiological needs. Feather pecking and cannibalism occur in all current housing systems and can lead to suffering and death in laying hens that have not been beak trimmed.



Issues Related to Beak Trimming

Beak trimming has elicited a great deal of debate and research concerning the relative advantages and disadvantages of the practice from an animal welfare perspective. The bestowed benefits of lowered aggression, feather pecking, and cannibalism may indeed favor improved welfare during the laying cycle. However, a chicken’s beak is a complex, functional organ with an extensive nerve supply. Following beak trimming, several anatomical, physiological, and biochemical changes occur in cut peripheral nerves and damaged tissues. There is a considerable body of morphological, neurophysiological, behavioral and production research demonstrating the emergence of several markers of acute and chronic pain (e.g., persistent lethargy and guarding behaviors, reduced feed intake, and development of neuromas) as a result of trimming. This is of more concern when the beak trimming is conducted in birds which are 5 weeks old or older using a hot-blade beak trimmer.



Hot-Blade Beak Trimming

There are several methods used for beak trimming in the United States but the most popular method is hot-blade beak trimming.  It employs a heated (650-750°C), ‘guillotine’-type, blade that both cuts and cauterizes the beak tissue when birds are 5 to 10 days old. A second beak trimming may be conducted on birds when they are 5 to 8 weeks old if a trimmed beak grows back.



Infrared Beak Trimming

Infrared beak treatment is an automated process carried out at the hatchery on 1-day old birds. Birds are immobilized using a head restraint and infrared energy is focused on the area of the beak requiring trimming. High intensity (radiant at 50 to 60 watt) heat penetrates down through the beak’s corneum layer to the corneum-generating basal tissue and inhibits further germ layer growth. After treatment the corneum layer remains intact until 7 to 10 days post-trimming after which the tip of the beak begins to soften and erode away with use.




Infrared beak trimming has several immediate advantages when compared to hot-blade beak trimming: 1) the elimination of open wounds that contribute to bleeding, inflammation, and pain; 2) better adaptation to eating because the changes in beak length and shape occur gradually over a 2-week period, which may better enable birds to alter their beak related behavior, resulting from a progressive adaptation, rather than an instantaneous change in the beak shape; and 3) a reduction in the number of stressors, such as catching, mixing, transfer, and handling, associated with the hot-blade beak trimming when it is performed on birds at 5 to 10 days of age. Long-term observation indicates that infrared beak trimming is more effective at reducing beak re-growth and resulted in less negative effect on feed intake and body weight than hot-blade beak trimming.

Until hens which express very low levels of aggression are commercially available or new housing systems are designed which better meet hens’ behavioral and physiological requirements for minimizing damage imposed by feather pecking and cannibalism, infrared beak trimming is a useful alternative to hot-blade beak trimming. However, the results of beak trimming are affected by multiple factors. It should be noted that the effects of beak trimming on bird well-being is genetic-, lesion- and age-dependent. A future approach for controlling feather pecking and cannibalism in chickens should be the combination of breed, housing design and management practices, which will provide a more promising option for preventing the need for beak trimming.





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