Head and shoulders above your others. The hens of those breeds are usually more than 10 lbs. Hatchery birds are usually smaller, but you'll probably need to account for their size when deciding roost height and nesting boxes size. I have a Brahma and a Cochin who are both quote large. I used to have higher roosts with ramps, but they would still jump down (rather than use ramps) and I was constantly treating bumblefoot. Now my roost is at 12 inches from the coop floor - about 6 inches above the litter level. No more bumblefoot!