@COChix sorry to hear you are getting rid of your chickens. But it does sound like you have made the decision based on what is best for you. Hope it all works out for you.
@Regina67 Welcome to the Colorado thread! What kinds of chicks did you get?
To answer your question, I did insulate my coop. I haven't gone through a winter with chickens yet, just ducks. They didn't really use the coop during the day but my run was pretty well covered to keep the wind and snow out. I was actually pretty surprised how much warmer is was in the run with just a plastic corrugated roof and clear tarps on the walls. That was with one end completely open on top and sides. I think the insulation works on the hot days too. The insulated coop stays a lot cooler than my garden shed that isn't insulated. They get about the same amount of sun but the shed is a lot bigger. Though now that I think about it, it could also be that I have more ventilation in the coop.

@Regina67 Welcome to the Colorado thread! What kinds of chicks did you get?
To answer your question, I did insulate my coop. I haven't gone through a winter with chickens yet, just ducks. They didn't really use the coop during the day but my run was pretty well covered to keep the wind and snow out. I was actually pretty surprised how much warmer is was in the run with just a plastic corrugated roof and clear tarps on the walls. That was with one end completely open on top and sides. I think the insulation works on the hot days too. The insulated coop stays a lot cooler than my garden shed that isn't insulated. They get about the same amount of sun but the shed is a lot bigger. Though now that I think about it, it could also be that I have more ventilation in the coop.