Well, you were right. Smelly. At least keeping chicks & eggs in same place, cause water for humidity got soiled. They're all hatched now & in a cardboard box with heat lamp, but temp fluctuates from 82 to 100 pretty easily. I'm thinking I might clean incubator well, take tray out of bottom & put in light cut up straw (which is what I have in their box now) & see if it works better. But I guess better longterm solution is a bigger box where chicks can go to warm or cold side if they wish.
The other thing I'm contemplating is putting my brooding hen in with them. It's too cold now to put the chicks under the hen in the coop, but if I put the hen in the box with the heat lamp (at night, slipping the 3-5 day old chicks under her), do you think she might take care of them so that I might be able to introduce them to the coop with the "mama" for protection & warmth in a month? Would the hen be unhappy in such warmth away from other hens? She is a frustrated mama as her & another hen sat on eggs all summer (long story) & I finally slipped out eggs & slipped in storebought chicks one night. But all the chicks adopted one hen & abandoned the other. Maybe these chicks will be her dream come true. Thoughts?