I'm just about finished with a coop so I can keep 6-10 pigeons for training. I'll probably use wild ones until next spring and then try to get some young ones homing so I can reuse them all next year. This stuff is a lot of work so I sure hope it pays off.....
Here's a pic of the inside (on it's back). It's going to have 6 nesting boxes that are ~ 24"W x 15"H x 14"D along with 4-6 perches....