Warning: go slow when feeding out
Never allow hungry stock sudden access to large amounts of a new food. Sudden changes to their diet can cause gastric upsets and can even be fatal. All new foods need to be gradually introduced to their diet, and as an option. As a general rule, none of these trees should exceed 5% of their dietary intake.
Some stock may take a while to learn to eat new foods, and older stock can show them how to do so.