Chicken tractor in cold weather

[Fire]

Here is an old pic of my tractor when I was building it.

I noticed my rooster a RIR seems to have the tips of his comb turned black. Im guessing this is frost bite? I live in Missouri so far this year it has only been in the teens maybe 10 at the lowest. 0 or below will happen soon. What do I need to do to keep my chickens from getting too cold? The vents at the top are about where the chickens heads are when they roost. I covered those up thinking that maybe that was making a draft. The coop is not insulated but is out of the wind. If I put a heat lamp or a 75-100 watt bulb will the light keep them from sleeping? Sorry for all the questions just want to make sure they are ok. They seem to be very happy and are laying well.

 

[Mahonri]

That's tiny, but yeah, I'd probably put a 100 watt bulb in there and see how they do.

 

[cw]

you could try a 100 watt red bulb if your worried about them making too much noise or not sleeping