I kept 12 in it until they were feathered last month. Right now I have 19 cuckoo marans that are 2 weeks old, and I'm thinking I'm going to have to split them up in a week or two. This batch had a lot of girls in it, so I'm growing them out to sell as started pullets. Your 10 should be fine until they are ready to move for good. I hang a heat lamp the same way, from the roof in the open part by the ramp. The feeder and waterer are under the roost. They stay under the light at night, and during the day they will be all over, upstairs and down. I mounted screws on the side, so during the winter I can hang plywood to cut the cold and drafts. Right now it is wide open. After about week 4, they start sleeping upstairs. I have 2 home made brooders, and this one. This one is my favorite. Like you said, it's not really built well enough to be a full time coop, but it's an awesome brooder.