Yes and no. We have heat lamps in the coop to keep the water open. But not to heat the coop, per se. It is on a Thermo-Cube and that shuts it off and on when temps get above freezing.
It gets down to -25F most years here in New England and this will stay open down to about -20F. The coop is about 20 degrees warmer than outside. So that means it's -5F in the coop vs -25F. So not a warm coop. Used this system for 10 years, has worked for us.
I know all the dire stories about fires, but we use 2 ropes to secure these, and they have the cage which would help keep the bulb from the bedding should it somehow fall. The light is recessed way up in the orange bell part.
Not to mention they are wired to the feed hose and would have to break loose from that too.
We also use lights as these are working hens. I can't afford to feed organic feed for 6 months and get no eggs. As far as it affecting their long life, they only live 18 months and become ground chicken. We tried keeping them 2 years but it just didn't pay. So we turn the lights on in late August/early Sept before the light gets too far from 14 hrs and leave them on until well into the spring. Our Rate of Lay is between 68 - 80% all winter.
We feed them extremely well, lots of supplemental things, they don't have to expend so much energy trying to stay warm, and they thrive over winter, as opposed to survive.
Ours are outside in their run as much as possible as the coop is really too small for so many hens. Some day, a large coop.....