I think it's a good idea. I have a peach tree in the middle of a garden that I let the chickens in to and they have never done anything to it. I feed all those fruits that you listed to the chickens and they love them. I have a friend who won't let the chickens eat peach pits as she believes there is some sort of poison in there to chickens, but like everything everyone has different opinions on that. I think, like you said, the chickens would do good pest control and it will give them a good place to roost in the shade.
