It does give off heat, but you'll have to confirm it's the right temperature for the chicks.
No. It is a infrared heat lamp.
The diameter of the bulb. Multiply 40 X 1/8" = 5"
We do not offer any Quartz Heat lamps. There are no LED heat lamps that I am aware of. LEDs generate very little heat when compared to an incandescent. Philips does offer a 175 watt PAR38 heat lamp (Model #145516) that uses 75 fewer watts than than the 250 watt BR40.
According to what I read, this bulb is not designed to be used outdoors.
For heat, but not artificial sun light
Yes, this is too hot, go to a pet store and get a correct bulb.
Yes... this bulb screws into it.