Molting? Winter? I have no clue

I have 6 girls. 2 Sexlinks, 2 Americaunas and 2 Buff Orphingtons. The girls have a 14 x 14 indoor area with supplemental lighting, and they free range at will (which is dawn to dusk). They get good food and plenty of water. They are less than a year old, all hatched within 2 weeks of each other.
First my Amercaunas stopped laying and started to loose LOTS of feathers around the head, neck and tail. Now they have pin feathers coming in. Then my Orphingtons were loosing feathers and stopped laying. Now they are looking better, and I don't have near as many feathers loose in the coop. None of these four a laying. My black and red Sexlinks are faithful champs and give me an egg a day, and have lost no feathers.
Aren't my girls too young to molt? I'm not so worried about them not laying, I'm chocking it up to winter (single digit temps). Maybe I'm wrong to not worry???
Any thoughts on this would be greatly appreciated, we are first time chicken owners. I did go pick each up today and they all seem very healthy!

I've read posts from other folks who said they had hens molt their first year. It may not happen often, but it does happen.

It does happen, especially it they are a bit older, closer to a year, you can tell if it's a full body adult molt by whether their tail and wing feathers get replaced, sometimes younger ones will go through a neck molt, which will halt laying but not as long as a full molt.

Almost all hens slow down laying during winter because energy is diverted to keeping warm, during really cold weather some will quit then resume when it warms a bit. The light can affect them somewhat but not like it does to older hens.

They are not too young to molt. I have had several 9 month old pullets molt. It's generally not a severe molt, but enough to disrupt laying.