one year later - help with coop redesign for frostbite

[Melky]

I purchased a weather tarp for winter
But have not a heat bulb. My coop manufacturer does not recommend it due to fire risk. I have not gone through a winter yet first yet to come. At what temperature do individuals start using heat bulb? Sorry to see the frostbite. I’ve heard Vaseline on the combs can help prevent frostbite. Interested to see further recommendations.