I haven't started to prune my fruit tress yet, so I would do a couple at a time and give the branches fresh. Same for willow or hazel.
Outer leaves of cabbages (or even inner bits if they are cheap), I grow Kale and PSB (for human and caprine use), soft bits of raspberry canes (not for goats that are in kid though), brambles, pony carrots etc etc, apple peel, bananas....