My 4 hens (of undetermined age) were laying most days through even the darkest weeks of winter (and that's with 16 hours of darkness up here). In the early spring 3 out of 4 hens stopped laying. I tried everything and then realised, to my horror and shame for not noticing, that they had a particularly bad infestation of lice. After a thorough treatment and quite a bit of nursing only one has started to lay again after several months but they all appear very healthy and are strutting around as sassy as usual. But... I'm still only getting 1 - 2 eggs a day, usually 1 from the gal who never stopped laying (bless her!). Is this a long term effect due to the infestation? The treatment (very conservative use of topical Ivomec)? Or is something else going on?