Pullet comb turning grey/yellow

[Notenoughchickens]

Hi everyone! Long time lurker, first time poster.

I have a 12 week old pullet whose comb is turning grey and has a couple yellow tips. A couple weeks ago we noticed two of our larger combed cockerels got VERY mild frostbite (there were a couple of damp nights around 0 degrees Celsius) which has since mostly sloughed off/healed. Around the same time I noticed this pullet had some slight grey marks near her nares, however it has spread up her comb in the past two weeks. She has not shown any changes in behaviour and is still active, eating, and growing. All of the pullets/cockerels are given free choice dry feed and fermented feed and are on pasture.
In the photos you can see the difference between April 30th and today. I’d also like to mention the white residue on her beak and feathers is from fermented feed.

 

[oldhenlikesdogs]

Looks like some mild damage perhaps. Either pecking, rubbing, or from the cold. It doesn't look like something I would worry about.

 

[Notenoughchickens]

Looks like some mild damage perhaps. Either pecking, rubbing, or from the cold. It doesn't look like something I would worry about.

Thank you! This is the first batch of chickens I’m raising from chicks so I just want to make sure they’re all as healthy as they can be.