I actually use buttermilk to moisten crumbles if I have a sick or injured bird I am treating. Likewise yogurt is good too, but I think buttermillk is better. Cottage cheese is another one I sometimes use for sick or injured birds. It is OK to give garlic once in a great while to healthy ones. White potatoes definitely not. Before I knew this, years ago I threw some white potatoes & peels in our
compost pile, which the chickens sometimes scratch around in. Shortly thereafter I had two hens sicken and die very quickly. I know they had both recently been in the compost pile
and I am sure they got hold of the white potatoes. .
Ours love watermelon...raw pumpkin and seeds...apples. Pretty much anything, lol.
if the potatoes start to sprout in compost pile they are not safe for chickens. I clean potatoes of buds and give to my chickens without any issues. the other thing that might have happened is that the potatoes peels were sitting on light and turned green. that is toxic too.