I am going to get into the backyard chicken business so I am setting forth to build a coop. I don't have tons of space but could probably do a 4x4, or maybe 4x6 coop with a small outdoor run. I want SMALL chickens (my friend has them), the name of which escapes me. My question is: how many such chickens would I be able to house happily in a small coop like I describe? Thanks for any advice!