I am seriously considering building a new coop out of cement (cinder) blocks. You know, the ones used to build basements. Has anyone built one out of this material? I don't mind the investment, I want something that rats can't chew through and is draft-free. We would incorpoate two windows and a door, plus a small access door to their run. Thoughts? Benefits? Draw-backs? Any information would be very helpful (and pictures would be awesome)... thanks!