combs turning white

I am completely new to chicken keeping, I have 4 hens and two roosters. All my chickens are a little over 5 months old and acting completely normal. Still eating, laying and running around like normal. Over the past few days I noticed one of my roosters developing these scab things on his comb...

hey everyone! i’m in ontario and the weather is -4 celsius today. my gals are healthy looking and have a heated water and coop (for nighttime). today i noticed my colombian Sunny’s comb is a little dry-looking? it’s white-ish and i can’t tell if it really looks that much different from september...

My niece called me about a friend that has chicken with her comb turning white. Does anyone know what causes this? I have been raising chickens for 5 years and never heard of this.