Hi again- If they have been laying for about a year, then it is quite likely they will be about to moult, that July/August/Sept time is the most usual for birds to change their feathers. In the normal run of things the breeding season is over, the chicks are pretty well feathered and looking after themselves so the adults now have time to take a break and change their feathers ready for winter.
Good layers will generally get it all over in one go. Less good will change their feathers a few at a time all through the year, so a tatty looking bird is often a better layer than a fine sleek one - she has put all her energy into looking good!
It generally takes a few weeks to change feathers, if it is a non-utility traditional breed it will probably go right off lay and if it is late in the year may not start again til the days lengthen in January. With a hybrid you might still get a few eggs, though with thinner shells.
Check the calcium content of your feed, and always have shell grit available, then they can adjust the quantity to their one needs. Also dried seaweed meal in a little feeder gives them access to extra minerals if they feel they need them.
I don't use salt in my cooking much, and every so often I long for a boiled egg with salt or a bacon sandwich, once I am salted up again I am fine, I think animals know when they are missing something. That's probably what leads to so much human obesity nowadays, The goodness we require is not in mass produced food, and our bodies are just crying out for the correct nutrients, while we just think we feel hungry and eat more - never felling satisfied
All the best with them
Sue