My crew of 11 are about 7 weeks old. Right now they are on a screened in porch in a baby pool covered with a tarp. The pool is surrounded by welded wire about 3 feet high. It's only the bottom half of the porch that is not screened. At any rate, the chicks are in the pool overnight from about 8pm to about 6:30a when we let them out in a temporary pen in the backyard til their coop is finished. My question is this...how long do they need their brooder light? Right now it's a 75 watt bulb...temps at night are now in the mid 50's...daytime temp in the upper 70's. I've tried turning off their light but they get real whiny and pile up on each other. I don't want to over heat them of course, but I don't want them to be dependent on the light either. They are all over the pool at night, not crowded together under the light, nor out on the perimeter to get away from it. They all seem comfy..until it goes off, then all he** breaks lose. Any ideas?