Owls have a totally different bone structure to humans, but the most important feature to familiarise yourself with is the breastbone, called the keel. Underneath your owl's chest feathers you will be able to feel a central vertical bone; this is the keel. The keel is the largest bone in an owl's body, and it performs two vital jobs: firstly, to protect the vital organs, and secondly, almost all flight muscles are attached here, to the keel and not the wings, as it is beneficial to keep the weight of the owl away from the wings for flight.

These powerful flight muscles are what enables the bird to fly, and can make up as much as third of the owl's body weight. This is why an underweight owl can be so weak and unable to fly well. Familiarising yourself with the keel while your owl is at a healthy weight will allow you to monitor their weight to a fair degree without much effort, and can alert you if their weight is problematic, ie drastically too high or too low.

On the topic of unusual bone structure; you may know owls have hollow bones to keep their weight low and facilitate flight. However, they also have air sacs all over their body to further improve buoyancy, and it is these that are affected if a bird with a weak immune system contracts the disease 'aspergillosis'. This shares many symptoms with other illnesses, so be sure to get your owl checked by an owl health specialist if they have any difficulty breathing, a decrease in appetite, or cyanosis (a bluish coloration of mucous membranes or skin).

The last significant unique feature a bird possesses that I shall talk about here is the feathers. You will already know that your owl keeps itself clean without any input from you, and you may know that this is done by 'preening': pulling oil from their oil gland through the feathers, to clean them and keep them relatively waterproof. For this reason, no matter how much your owl enjoys it, it is best to avoid touching the feathers most useful for flight; more specifically, only stroke your owl on the chest unless otherwise necessary. Further, strokes on the head are best avoided altogether, as these can be construed as 'courting' for owls, so this can be unsettling or misleading for them! This can often explain why some owls develop jealous behaviours towards their owners...