So you mean inside your house? Or inside a barn? If they are inside your house, how do you have room for all of them? Or do you just not have very many? I'm wanting to build pens inside my horse barn next Spring. I'm running out of space and I need more pens! What is your set up like for them?My Silkies have it pretty good. Living indoors they may not get much sunshine, 'cept what comes through the windows, but they get greens everyday, either store-bought or from my lawn and garden, they never have to worry about predators, especially since they can't see the airborne variety, and they are protected from rain, snow, and bitter winds. As for "proper" coop materials, it really boils down to what works best for each person, not what is "right" or "best". I worry a lot less about my indoor birds than I do about my outdoor birds. Guess it's a similar argument for why some people are against cats being let outside. Just like neighborhood cats killing birds, I don't ever worry about my chickens decimating the local bug populations. LOL