I've been doing more thinking (sometimes I do too much!) and wondered if a concrete slab floor would work in a coop. We have a pressure washer at the house and I couldn't help but think how nice it would be to just sweep out the bedding and use the pressure washer to clean the floor (we can add a "solution" to it I.e. Soap and/or bleach). Cement can withstand plenty of abuse, is easy to clean and is predator proof!