My hens stopped laying... WHY?

Hi again (to those who read my chick post)... One other question on a different topic.

I have two adult hens. Got them around Halloween last year and they went right into laying regularly - about an egg every 3-4 days between the two of 'em. I originally got 3, the hens and a pullet... well... the pullet was apparently a cockerel and a few months ago decided he wanted to ummm... get jiggy with my chickens. So we found him a new home (we're inside city limits and can't have roosters). The ladies went on strike and didn't lay for about 2 weeks, but then got back on track. Several months later (now), they've stopped laying again. Our weather is warming up (and they layed all through the freezing temps and snow), our days are getting longer (plus they have artificial light equalling 15hrs of daylight) - which I just bumped up to 18hrs to attempt to get them to lay.

I don't understand why they aren't laying. My buff one (these are both Plymouth Rock hens by the way) seems to be losing a lot of feathers around the yard, but doesn't have any bald spots or anything... so I thought maybe they're molting... but the barred one doesn't seem to be losing any... so???

I'm at a loss. I got 5 eggs the entire month of March and most of those were in the first half of the month... I haven't gotten an egg in 3 weeks now. I've searched the yard to make sure they aren't hiding them, but I don't see any... and there arent any good hiding places to speak of.

Any suggestions on how to get them to resume laying??

Thanks!!!

PS... I should add... prior to stopping, they'd gotten into quite a rythym. I was getting an egg every day for a few days, then TWO eggs in one day (one from each I assume), then they'd skip a day or two, then start over. I was getting nearly 2 dozen eggs per month. Then nothing.

 

I don't think they're broody, nor eating the eggs. They did have a few shell-less eggs right before they stopped laying (though they have free access to oyster shell). They both sit in their self-designated laying box (they both only lay in that one box, even though three are available - they both sleep in another & nobody likes the third... go figure), but only for maybe 1/2hr once or twice a day.

How long does a moult usually last? I continue to see little buff feathers all over the place, though she doesn't LOOK like she's missing any.

I also just realized they have caked on pooh (see my post in the disease section)... could that have anything to do with it? It's not blocking, and they have normal stool, though a lot of eggshell substance seems to be in it. See my other post for more details on that.

Anyway... I appreciate all the feedback. Guess I'll cross my fingers that it's just moulting and I'll get eggs again eventually. I'm not sure how old they are (they were given to me as adults by someone getting rid of their flock), but I don't think they're old enough to stop laying.