We were there in May and I'd say the chicken was about 40% white meat - breast and wings. Remember there are also ribs served. We thought the food was good and the show was great! Have fun!
My family is the same way. We always ask for specific pieces after the waitress brings the first round. they have always been more than accommodating in bringing more breasts and wings.
As was said previously, the first batch of chicken is mixed but we have been there numerous times and the waiter (waitress) always has bought us as much white meat as we could eat, so