I have also given mine pineapple and they loved it. I wouldn't give them a large amount because, like citrus, it contains a fairly strong acid. That being said, I do occasionally give mine an orange or two - neighbor with an orange tree.
We toss out the pineapple peelings and even one that got a bit too soft for our tastes. The flock went wild. But they do that for apple cores, peas and carrots, cucumbers, turkey. Not too discriminating, but they put on a great show. Mine won't eat citrus.