We used them for pigeons. Pigeons only lay a couple of small eggs at a time before they will start to sit. They laid eggs in the center portion of the spool. You can see where I cute a hole out for them to get into.
I feel like I need to give an update on this project since it has been revived on Pinterest and Facebook. It's been about 4 years since we made these. Since then, we have discovered:
(1) Since spools are not treated wood, they decay very, very quickly. Right now, the pens are a pile of trash waiting to go to the landfill. We are going to strip the wire from them and dispose of them.
(2) These are WAY too small for people to raise standard chickens, rabbits, pets, or larger bantams in on a constant basis. *IF* you use them just as coops, they work well for pigeons (like we used them for) or for small bantams like seramas. Our roller pigeons used these as nesting areas and we let them out on a daily basis to train them. I would not recommend them to keep poultry penned up without access to roam/fly.
(3) The chicken wire works to keep pigeons in, but is not very secure if you have predator problems. We are fortunate to not have a huge number of bad-to-the-bone predators, so this type of wire worked well for us.
(4) Would I make these again? No. They were too much work for just a short time of use.