First time chicken mama here. When can I remove the heat source for my girls? I have 4, 4.5 week old pullets. They are all feathering in very well and I'd say almost completely feather (except one girls seems to be slightly behind). Anyhow, I currently have a brooder heating plate, but the girls seem to be spending less and less time under it. Since they are getting so big and it takes up a lot of space in the brooder, it would be great to take it out ASAP to free up more space for them. They are in my garage which generally stays between 60-73 degrees F (depending on outside temps). I was thinking about taking it out this weekend and using a heat lamp as a backup heat source for night time (since that's when it usually gets down to 60). Does that sound like a reasonable idea? When should I be able to remove heat all together? TIA!