Agreed in everything - and I, too, prefer the ceramic heat emitter...Yes you must clean it off, this is pasty butt and can be fatal if not attended. I am guessing your setup is too warm. Put the heat source at one end and use a thermometer to verify they can get to a cooler (room temperature) area. You could use a smaller bulb, just a normal incandescent bulb, say 75 watt for just 2 chicks. It would need to be lower, in that case.
I used a ceramic heat emitter, (reptile bulb) in my clamp light fixture and liked that a lot.