This is our first time with chickens...I read in books and on many threads here how fast chickens grow. But WOW I can NOT believe the changes in just one week! Its amazing to me!! Anyway, my husband is building a coop. We were wondering how big does the opening have to be for them to get in/out? How big do nesting boxes have to be? We don't know what kind of chicks we have so we're not sure how big they will get. I was thinking a 12x12 nesting box? Does each chick need their own? For the inside of the coop, what do you guys put down (I've read pine shavings are good)? Can you put a rubber mat underneath it so it's easier to clean/hose down? The coop is going in a big dog run. In the dog run are we supposed to put pine shavings down? Or just let them hang out on the grass? Maybe a little bit of both? Lol I'm sorry for all the questions but we just want to make sure we're doing it right. We want them to have lots of space and be happy. Any other advice is also greatly appreciated !!