There are many animals in Avalon and the majority of these will require access to suitable food - to maintain their health and keep them alive. This applies, specifically, to livestock, farm animals, vermin and critters (see HELP CRITTERS), most pets and steeds (including eagles) and most birds (including all those reared as part of Ornithology and Falconry). You will be able to use your Itemlore skill to PROBE an animal to quickly discover its state of health/hunger - and should act accordingly to ensure it is provided with food if it is your responsibility to do so.
There are three types of animals, in feeding terms: herbivores, omnivores and carnivores. Starvation can press an animal into emergency measures, but most have preferred eating habits which can be learned over time.
Most farm animals and livestock are herbivores and can be kept well-fed by ensuring you graze them regularly on a meadow or grassland. Troughs containing wheat, bread products, fruit or large amounts of seed will also sustain most herbivores. Rabbit hutches and pigeon lofts should also be filled with such foods. The carniverous animals are more difficult to sustain since they require meat, which can be expensive, or critters (like mice and small woodland creatures) to remain healthy. Birds of prey, particularly useful as steeds - if sufficiently large - or as familiars - if one has suitable skills - are particularly voracious in their appetites but have the advantage of being able to patrol the skies and swoop down anywhere on the ground below, to pluck a suitable critter when hunger dictates.
If you wish to pro-actively feed an animal, as opposed to simply grazing it/leaving it in a location well stocked with provisions, type FEED followed by the item you wish to use as food, followed by the animal to whom you wish to give the food, e..g. FEED BREAD TO LAMB or FEED MOUSE TO FALCON to feed bread to a lamb or a dead mouse to a falcon respectively. This feeding has the advantage of building the health and resilience of the animal, bolstering it against future months where there may be a dearth of sustenance.
You will find animals, especially when hungry, to be agreeable when presented with tasty vittals and it is not unknown for most livestock, farm animals and critters to allow their fundamental loyalty to be affected if their owner has allowed starvation to set in and some kind soul comes along to feed them back to full health. The person responsible for that life-saving provision of sustenance will then take over loyalties of the creature/animal.
See HELP CRITTERS, HELP BIRDS, HELP STEEDS and check out your Farming and Labours abilities for further detailsd of skills and processes relating to animals; and pay a visit to the libraries if you wish to seek out books detailing the specifics of animal husbandry.