We moved our hen to a separate pen so she could hatch some chicks.. She hatched them now, but since it's winter, we'll leave the chicks in the pen so they can have the lamp.. But how long do we leave her in there?
Why not leave her with them, they won't need a lamp at all. Or if you're able to supervise a little, give her a few days then put her back with the flock. That way she raises the chicks, you don't have to fuss with brooding, and the chicks grow up knowing how to fit into your flock. It's really the best way all around. If you can't/don't want to put the babies back in general population, leave the hen with them until they're about six weeks old and they still won't ever need a heat lamp, at that point they'll be feathered enough to be on their own.
They don't need the lamp, but it's best to leave the mother with the chicks for a while. She will teach them what they need to know. We keep our hens with their babies confined in a pen, for about five weeks. Ours free range, so after that we let them out so she can teach them what they need to know in the bigger world outside. She "weans" them at about seven or eight weeks.
