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Pathing individual performance, welfare indicators and behavior to keel bone alterations in chickens


Year: 2022

Kristina Mertens
University of Bonn, Germany

Supervisor(s): Dr Inga Tiemann


Keel bone fracture in laying hens is currently a very important issue in terms of animal health. Studies have shown that this problem is present in up to 80% of all laying hens in a flock. The bones of hens are very susceptible to fractures probably due to high calcium expenditure during egg laying and thus reduced calcium availability for bone development

It is thought that fractures can be caused by stress in the group, by collision with equipment or furniture in the hen house, eg when landing on a perch, or even pressure on the bones due to the weight of the eggs produced (especially in young and smaller hens).

Breastbone fractures are difficult to detect in hens whilst alive – as although in chronic pain, hens may still show no change in egg laying performance.

This study seeks to identify behavioural traits and other welfare indicators that may help to better identify keel bone fractures.

The behaviour of 10 laying hens from each of 8 different breeds of the domestic chicken and other welfare indicators will be recorded over their lifetime. Hens will be tested on their response to novel objects and reaction to an unfamiliar person; it is hypothesised that hens with fractures may show reduced mobility and reluctance to move. After slaughter (standard farming practice post lay) their carcasses will be examined for fractures and healed fractures and location of these recorded fracture. This information, along with the behavioural data, will then analyzed using GLM models to identify risk factors and correlated indicators for the whole life span of an individual.