Change in behaviors

[newbie55]

Hi all. My Buff Orphs are 18 months old. Up to this time they have been talkative & productive egg layers. Lately, I have only one laying eggs, one has lost feathers down to the shaft on her chest. I suspected mites and washed out their coop. For a few days I wasn't getting any eggs and did not see that that they were laid in the back corner of the coop hidden by straw. Their whole attitude has changed and this morning I have one just sitting on the perch with the coop door wide open and she doesn't go out. What could cause such a change in their behaviors?

 

[ChickenCanoe]

An 18 month old chicken in September, losing feathers and not laying is molting.
Molting birds feel like crap. They can't ovulate when they are using all the available protein to build feathers that are 93% protein.
You'll get eggs again when they have completely regrown a new winter coat and possibly not till after winter solstice when day length increases.