It's great to be able to reuse old structures for coops!
Chickens need LOTS of ventilation in their coops and they, being birds and not mammmals, do not need to have a heat source in the coop except in the most extreme conditions.
Your coop looks to be severely lacking in ventilation. It would be ideal if you could cut the top 6 inches of sheathing off the front and back of the coop and cover it with 1/2" hardware cloth on the inside and outside. I would also add two top hinges windows to the coop for light. Back the window openings on the inside with 1/2" hardware cloth too.
You've got a good start!
Thank you so much! We are definitely adding some windows for ventilation. With how we are making the run, our lovely ladies will have nice air flow and it won’t be stuffy and they should have plenty of light. Thank you for your amazing advice!!! ?