WOW that is a lot of pens!! Yeah...but I don't breed...and here by me the BYM is a very popular bird!! I would have let me say 200 chicks and they would go in maybe 2 hours....Yep Barn Yard Mix are Pretty. But people turn their nose up at the Auctions when Mixed Chicks go across the Auction Block---Being I sell I do not want Mixed. Having more pens is Nice but creates more work with everyone you add. I Know because I have added and added now I am up to 57 pens--besides the Hatching pens the pens range in size from 50sqft to 1 acre in size.