I'm building a three tiered hutch for my future quail (incubator is in the mail!) and am worried I'm not going to be giving them enough head room per pen. I'm sort of following this design https://www.backyardchickens.com/a/the-cage-page-japanese-bantams-coop but using precut 2x4 panel pieces, so each pen will be 4Lx2W with 3 pens within a 4 foot high space. It comes out to roughly 15 inches per pen. Here's the problem. I'm going to flip the shelves over and, using 1x6s, make each pen capable of holding deep litter, thus potentially reducing the space to only 10ish inches per pen (though I doubt I'll get that much litter in the pens, it could happen.) I'm hoping to get the jumbo sized cots and, potentially, have 4-6 birds in each. I'm wanting to make sure my birds have lots of space and are comfortable, but not so much that they break their necks. (I wish I could put them in the yard in a tractor, but between the lawn service, snakes, huge geckos, ospreys and eagles, I'm thinking that for now, they're going to be penned/caged birds in my pool area.) Thanks for any insight/info/comments!