Threads about frostbite can be educational to see the danger of what may happen to combs, wattles, and feet, when exposed to freezing temperatures. Every Jan/Feb we read about severe cases. The OP’s rooster was accidentally locked out of his coop in freezing weather. Sometimes a chicken gets locked out, and a predator kills the bird. We all learn from a mistake or an accident like this, and I have learned early on to do a head count when mine go to roost. That is why I have never wanted an automatic pop door.
When coop humidity is high from a lot of birds breathing, and not enough overhead ventilation, we see frostbitten combs. I keep metal garbage cans for feed, and those can be a danger to feet if a bird decides to roost there. Water spills or open bowls that are stepped in are a risk to feet and wattles. Highly soiled bedding is another good way to get frozen feet.
Hopefully, this thread can be helpful to others.
When coop humidity is high from a lot of birds breathing, and not enough overhead ventilation, we see frostbitten combs. I keep metal garbage cans for feed, and those can be a danger to feet if a bird decides to roost there. Water spills or open bowls that are stepped in are a risk to feet and wattles. Highly soiled bedding is another good way to get frozen feet.
Hopefully, this thread can be helpful to others.