One may untie bunches of sheaves in front of cattle (for whom it is food). One may scatter fresh shoots (because this is necessary to make them available to the animals) but not tightly-packed straw (because this is more effort than needed). One may not chop immature grain or carob for animals, whether large or small (as this is also unnecessary exertion), though Rabbi Yehuda permits one to chop the carob for small animals (whom he feels would have trouble eating it otherwise).
One may not feed a camel to satiety on Shabbos (as one does before a journey), nor may one force-feed it, but one may put food in the camel’s mouth. One may not force-feed calves, but one may put food in their mouths. One may put food into the mouths of birds and one may put water in coarse bran for use as animal feed, though one may not knead it. One may not place water in front of bees or doves in a coop but one may put water in front of geese, chickens and other domesticated fowl.