I converted a chicken tractor to a small coop by taking the wire off and putting 2x10s under it to get it off the ground. It was build for 3 hens with a nest box. I now have 5 young hens and pullets. I took the nest out to make more space for roosting. About a month ago I built a nest box from a 5 gallon bucket and put it beside the coop with 2 fake eggs. I meant for this to be mainly temporary until I got around to building a wooden one. My 3 speckled Sussex started laying a couple weeks ago. They really like the bucket and haven't laid anywhere else. I think the fake eggs helped a lot. I'm getting the cleanest eggs I've ever had. My barred rock and my Rhode Island Red should start laying soon. They are a little younger. I believe they will all grow a little more.
Will mature chickens of these breeds be too large for this bucket? Is one nest enough? Should I drill a few ventilation holes for when the weather warms up?
On a side note, I had an unexpected problem with using a chickentractor. The fenced part of my backyard was full of young dwarf apple and pear trees. I lost most of them to fireblight. I believe the excess fertilizer from the chickens made the fireblight worse.