runny nose clear, normal?

[Schnayke]

So one of my chickens has a runny nose, I just noticed it today, and wondered if this is normal for birds in cold whether, too be fair I have a runny nose right now too, but no cold its just cold out.
She seems to be fine otherwise, it gets down in the 20's at night sometimes around here but normally in the 30s during winter. I don't provide any heat for them, but do close up the coop at night, and close the windows at night.
She is eating fine, pooping fine, seems to be acting totally normal outside of the runny nose.
We have only 2 birds. the other seems to be totally fine.

 

[Jadore Poules]

I asked my vet about this very thing as I noticed it in my chickens, too. He said that sometimes, when there's no rasp or other sign of illness, clear discharge may be caused by temperature change. In fact, my chickens exhibit a bit of clear fluid when they come out of the coop in the morning. I've not had a lot of experience with chickens however, so maybe someone else knows more about it. Just wanted to tell you what this other "New Egg" has experienced.