For the safety of the birds I'd put them in a room away from the kitten! Some cats have more "prey drive" than others, but the bigger Oreo gets, the easier it will be for her to kill your birds. I had a parakeet many years ago that was in a cage hanging from the middle of a ceiling so the cats couldn't get near the cage. Well guess what? I came home one day to find the cage on the floor and not even a feather to be seen. Apparently one of the athletic cats had managed to leap up and yank the cage right off the hook...and that was that.