Why aren't my chickens starting to lay again

[Wills]

I've got 4 chickens and only one is laying each day. Another lays approx 1 every 3 days and the other two (supposedly the best egg layers) are still off lay from the winter. Last year they all laid all year round, this year as the nights drew in they slowed down and almost stopped, but with the nights drawing out aren't they supposed to be laying again. We treated last week for worms (just in case). Any other ideas as to why they're not laying?

Commercial farmers only keep hens for the first couple of years of highest productivity then.. chicken soup.

Some farmers provide artificial light to keep their hens laying when normally they'd rest.

Hens need to recover after intensive egg laying, this is normal and necessary and can last months.

As I don't know how old your hens are I'd say they were over 3 so this is completely natural. Keep them well fed and happy and you can have eggs (probably not daily) for several years to come.

My 8 y.o hen hadn't laid for a few years then one spring she laid a clutch then not again until her demise.

My hens are only 2 years old so its partly why I'm confused.

Red mite?

Can't see any. When we've had an attack before we've been got by them as well, also they don't look like unhappy birds.