If you're in the Northern Hemisphere, it is absolutely the time to be molting, although you're right, they don't usually do a full molt in their first winter. But chickens love to break all the rules, I'm finding.
Do you see a clump of feathers under where she roosts? If so, I'd guess - and this is COMPLETELY a guess - that it's a sign of molting.
If you think any of your flock might be going through molt, be sure that they have adequate protein support in their feed, as growing new feathers is a protein-demanding task. Many people use a 20% or higher feed during this time, if not year-round. I know that Kalmbach has a feed for feather support, although I've not used it (yet.) I'm an admitted Kalmbach fan girl, but I'm sure that other manufacturers have something similar. Alternatively, you can supplement your regular feed with additional protein, especially animal protein like sardines (yuck) or ground beef (many other options including mealworms, soldier beetles, etc., although they're also a bit fatty.)
https://www.kalmbachfeeds.com/produ...Rnltbz4-J2lqWudu1ig-_97WMv0RPOSusKqeQOPa9bk2h
Edit to add: this particular ^^ product is meant for layers, with a 3.5-4.5% calcium content. So if you have roos or other non-layers, you'll want to look for a similar product without high levels of Ca.
