Veterinary Public Health Institute, Animal Welfare Division

Spring Semester 2018

Keel bone damage, such as keel deformation or fracture, has become one of the major welfare problems of the egg industry (FAWC, 2010). It affects a large proportion of laying hens in commercial housing systems, with between 56% to 97% of hens effected in a flock (Rodenburg et al., 2008; Käppeli et al., 2011; Wilkins et al., 2011) .

In the course of my master thesis I am researching the effects of keel bone fractures on the behaviour of laying hens. Therefore, 80 individually marked hens in eight experimental pens were recorded at two time points for 5 hours each distributed over two consecutive days. To study whether any behaviour alterations are due to pain, the hens were treated with an analgesic in their water supply for one of the two time points. Administration of “analgesic + water” or “water” was balanced between pens, hybrids and time points. To assess the keel bone status, the hens were x-rayed and the images will be scored using the scoring system developed by Christina Rufener.

Furthermore, I investigate two animal related risk factors (activity and reaction to a novel object) of hens without fractures and see if the same hens obtain fractures at an older age.