Using naturally-occurring variation in beak morphology to reduce feather pecking damage in laying hens

Feather pecking is a welfare concern in laying hens. Blunt beaks may be less able to grasp and remove feathers/tissue; however, the relationship between beak shape and the ability to cause damage is still unclear. Two studies examined pecking damage between hens with different beak shapes. The first used laying hens sorted into two groups based on beak criteria (sharp vs blunt). Hens pecked at a “chicken” model (foam block covered with feathered skin). Feather number, skin/block weight (proxies for damage), and the number of successful (feather/tissue removal) and non-successful pecks were recorded. Sharp beaks removed more feathers and had a larger change in skin weight and more successful pecks. The second used a robotic device to imitate a hen’s natural pecking motion. Heads of hens with differing beak shapes were collected, attached to the device, and ‘pecked’ into gel (mimicking muscle) at three different forces. Damage was quantified by measuring the gel indentations. No differences in damage were found between the beak shapes. Sharper beaks were more capable of removing feathers and making more successful pecks. However, the damage data suggests that factors beyond sharpness (other beak shape traits, behavioural motivation) may also play a role. The dataset is related to the PhD thesis “Using naturally-occurring variation in beak morphology to reduce feather pecking damage in laying hens”; candidate: Sarah Struthers.