the best way to sex chicks is when they are a day old. The female's wing feathers will be longer than the rooster's by quite a bit. It's easy actually once you see a comparison. Check youtube for a video and you will see how easy it is.
I have always put my chicks out when the temps stayed above 50's at night. Of course they get a lamp until it gets much warmer and/or they're fully feathered out. Yes, having them in the house is an ordeal we all must go through, but the end result is so rewarding! Keep thinking about all the...