I've just built a new 5' x 10' loft to house my old bird flyers. On each of the end walls ( which is the 5' dimension), I will have 6 nest boxes. On the 10' dimension there is a window which will have a sputnick. The birds will be flying natural, not widowhood. I thought I remembered reading that to encourage nest box possesiveness, there shouldn't be any perches. What do you think?