What is the ruling on selling pastries left over from customers that are not damaged, and what should be done with the half-eaten ones, knowing that he collects the good ones and the eaten ones and gives them to sheep, some of which contain meat?

The restaurant owner is permitted to take food left by customers and benefit from it, whether by selling it or consuming it, as long as its owner has relinquished possession of it. However, the nature of this food (such as being reheated or previously served to a customer) must be clarified to the new buyer, as it diminishes its value and the buyer's desire for it. As for offering edible pieces of food containing meat as feed for sheep, there is no harm in it, provided it does not cause harm to the animal or human.