More likely too little ventilation.
Does the water add humidity or make the bedding wet?
I have a remote hygrometer that I move from coop to coop. If it is more than 10% higher humidity in the coop than ambient, I know I have a problem.
All my new coops have huge hardware cloth covered windows...
It could be mild frostbite but doesn't look serious. Don't close up the coop. That causes a humidity buildup which contributes to frostbite. I'm sure it gets colder here than there, my coops are wide open and my roosters have much bigger combs and wattles than rocks.