There's something wrong with 5 of my 6 girls. This has been going on for several months now:
The original girls (red sex-linked) will be 4 next spring, but even though I"d expect them to lay less now due to their age, they've totally stopped. Two of the three younger hens (New Hampshire Reds) are also not laying. I find one egg every other day or less, presumably from the one NHR that looks healthy.
The affected hens' combs are pale.
One or two of the NHRs are losing feathers, but they're not a year old yet so I presume it's too early to molt? That seems to have slowed down some in the past week or so, thank heaven (no longer looks like an exploded feather bed in the coop).
Also, the feed level in the feeders and the level in the waterers have not been going down nearly as fast as they should be. That seems to have improved in the past week or so. However, I do think at least some of the hens are on the skinny side now. To help with the weight and regrowing feathers, I've been using BOSS instead of scratch and mixed game bird feed or Feather Fixer in with their usual laying hen feed.
The only stressor I can think of is that there's a stubborn squirrel (I think) that climbs through some opening in the old shed roof (my coop), through the wall of the roosting room, and out into the front room. Could that scrabbling noise passing through really be enough to cause all this in my 5 girls? Or is there some disease going on?
BTW, last spring I made the run area in front of the coop as wild bird-proof as I could. I still sometimes see a few juncos or sparrows in there, but mostly not. So, I'm thinking the chances of their catching something (illness or parasites) from wild birds is pretty limited. I've periodically added Rooster Booster dewormer pellets to their feed, and did so again last weekend, but this time they're not eating it.