I have 3 chickens-- Australorp, Easter Egger, and Barred Rock. They will be two years old this Spring-- 2016. Prior to last fall, they all seemed happy and were laying regularly. (There was a brief period of a problem with pecking and feather loss early-mid last year, but I deduced that was out of boredom and I placed more objects and straw in the run, and that resolved the issue.) Then, last fall they all began molting and egg production slowed, then stopped. Their last production was in mid-November 2015. I wasn't worried at first-- I know molting can stop/slow production and there was also the onset of Winter (I live in Cleveland, Ohio), and I don't provide any alternative light source, so I expected low production. But, they have not produced a single egg since, and it is now nearing the end of February.
They seem happy and normal, otherwise. They are all eating regularly and their plumage fully returned a while ago. I feed them commercial layer pellets and supplement with black sun flower seeds, puppy chow, and kitchen scraps. Other than not laying, their behavior seems normal, except they seem to spend a lot of time in the coop, rather than the run (but, I assume that is just because of the cold). I was concerned that they might be laying and one or more eating eggs, but there is no evidence of that-- no shells pieces or anything, and they haven't been sitting in the nesting boxes, which they used regularly and with no problems until last November.
It's been 3+ months and it seems strange that they would all stop producing at the same time and for so long. Is this normal (or, at least, not abnormal)?
Thanks in advance for any information and/or advice.
(worried chicken owner)