my buff orphington's comb points are changing color

[nannys chicken]

I have three chickens; a barred rock, an ee, and a buff orphington; each chicken is 9 months old.
All three birds appear healthy and have continued laying, even during the below freezing snap, that New Jersey just experienced, last week.
My orphington is gorgeous, but a couple of the points on her comb are changing color....brownish gray, and feel dry.
They are in a coop outside, that was kept above freezing, with a heat lamp, during the week of deep freeze.
Any ideas of what I should do for her comb?
What can it be?
I'm new to raising chickens, so I feel anxious about the change.

 

[Eggcessive]

There is probably some frostbite on the combs. Many use Neosporin ointment, vaseline, or coconut oil on the combs to treat this. Make sure your coop has plenty of ventilation high above the heads to let out moisture--this may help to prevent frostbite. Heat lamps are not necessary unless temps are below -20 with proper ventilation. Here is some info on frostbite:
http://www.tillysnest.com/2013/01/frostbite-and-backyard-chickens.html
http://www.the-chicken-chick.com/2013/12/frostbit-in-backyard-chickens-causes.html

 

[Eggcessive]

Here is an excellent article about coop ventilation from someone who lives in Canada: https://www.backyardchickens.com/a/...-go-out-there-and-cut-more-holes-in-your-coop