I have a pullet about the same age who is in fact doing a full molt. It was disappointing because she quit laying to do so, but not all that unusual I’m finding out.Their coop is 6x8 with an 8x14 enclosed run. I let them out to roam about 5-6 hour a day. No rooster. I’ve talked with other chicken owners near me and some tell me they had pullets lose feathers at this age although not a complete molt. Others say no feather loss. Leave it to my girls to buck the system.
As the other responders have already said, if they’re healthy and active, no parasites, have well balanced food and shelter from the elements they will be fine.