I haven't used a carrier, but I have used a metal large dog kennel. Mine is wire on top. I actually thread the cord through the top and have the lamp on the inside. It has an adjustable dial on it so I can change the heat level.
How many chicks are you putting in there?
you can run a wire between the two wire ventilation panels and run it through the little circular ring in the clamp part of the light, if you are using clamp on lights. That way it can NEVER fall and cause a fire. You can raise and lower the light by loosening and tightening the wire. Put it toward the front of the crate so some of the heat can dissipate out the door and they don't overheat, or put a thermometer down there and REALLY check the floor temps.
just get a thermometer in there and make sure that for the first week there is enough room for each bird to have a 95 degree temp... and drop the temp five degrees each week until you get to 70 degrees by that time they should be full feathered at which point they are ready to go outside...