My chickens have always molted around October. They will have a "minor" molt their first year but it is hardly noticeable with the young pullets.
Moving the birds, a change of diet, or illness may also prompt a molt.
If the birds do not have access to the outdoors, I suppose that they may molt at anytime of the year. And, the timing would likely vary in different parts of the world, as well.
Usually, they cease egg production during the molt altho' there may be a few eggs.
(And finally, I hadn't expected someone from Missouri to spell it "moult" . . .
My birds didn't go through their first real molt until they were over a year and a half. They had some mini molts. They didn't stop laying altogether but did slow up alot. They do free range. They have access to their yard 27/7. I hardly ever shut the pop doors even at night.