When looking at joint diseases, pain, swelling or stiffness at the joint, both doctors and vets consider a ‘normal’ range of motion for a particular joint to establish whether there is any limited range of motion. A wide range of data exists for humans and dogs for example, but little is known about joint range of motion in broilers or even other birds. For broilers, it is possible that they may have a limited range of motion in their joints, which likely impairs their walking ability.

The Royal Veterinary College (RVC), under a BBSRC-funded project, looked at how much joint range of motion changes as these birds progress to market weight, over only 42 days and what percentage of this joint range of motion these birds actually use when they walk. RVC used a motion capture system to obtain joint range of motion by manual manipulation of the joints using cadaveric specimens and presented our preliminary data at ICVM 2013 in Barcelona.

The college researchers found that range of motion increased in the more distal joints, with the range of motion largest at the ankle. This makes sense when the majority of their muscle is concentrated around the hip and the knee, and these muscles will restrict movement. What the researchers found interesting was that in the six week old birds the ability to flex and extend the knee joint was significantly reduced and so was the abduction/ adduction ability of the hip.

The RVC researchers would perhaps expect to then see that these older birds would try and use as much of that more restricted range of motion as they walk. However, they found that when these broilers walk they still use a similar range of motion at each joint whether they are two weeks old or six weeks old.

Broilers therefore seem to have a limited range of motion at the hip and knee at six weeks old.