My chickens love oranges....they don't eat the peels. They love most fruits...and lay eggs regularly. I'm saying that cuz someone will come on and say...don't feed them fruit cuz they will stop laying. My chickies eat lots of fruit, especially in the summer. Haven't tried grape fruit, tho.
we started with soft treats at first. bananas, plain yogurt and such. we can't remember exactly when we started giving them treats, but they were little. it's alot like little kids, you can't remember all the details.