I agree with Little Blue - we have had really sick goats, down on the floor, no interest in eating, but cream crackers were eaten!! I also warm some water, add couple of teaspoons of bicarb to it, had sick goats drink that, and it does help their digestion. A little molasses or treacle on top of the feed is another tempter, oh and bananas and digestive biscuits. Believe me, I have had some desperate times over the years, so have tried all sorts to get them to eat.
Bit early for leaves, but the bark on willow branches is good too. Got pain relief in it.