I have been scouring the interent in search for answers when I came across this thread. Our own flock has the EXACT same thing, I think!!
Ours has been going on since Saturday (2-4-12). We noticed on Friday that one of the chickens were not "happy". He didn't seem to engage with the others and wouldn't jump back up into the chicken house on his own. The next morning, he and another chicken were extremely lathargic and not moving around alot. Within two hours, they have both laid down and died.
This is our background story:
Our flock consists of seven white leghorns that were born sometime in October 2011, and twenty-one chicken that were ordered from an online source at the end of October. That internet order included Plymouth Rocks, Brown Leghorns, White legorns and some "males shipped for warmth" and we do not know what breed they are, but they look and have grown alot like broilers. We have been planning on processing these seven "broilers" very soon. We just have been waiting to get the nerve. (This will be our first time). So, we were hoping that these two dying was just a fluke, like they had grown too big for their hearts to handle, and nothing else would happen to the rest of the flock. This was NOT the case...
Sunday morning when I let the flock out, another "broiler" was acting the same as the two the day before. Within a few minutes, he died, too. We had another "broiler", and now one of our Plymouth Rock hens acting a little funny, too. But after they started feeding and drank some water, they seemed fine the rest of the day.
This morning, I woke to one of the Plymouth Rock hens that had already died, and another "broiler" and rock acting extremley lathargic (who died a few hours later) and it looks like we might loose another rock. This will make the total up to seven dying mysteriously!
Other than the lethargy, there are no other signs of sickness. They are gaining weight properly. They are not overweight. Before these episodes, they are happy and healthy. No diarrhea, no runny nose or eyes, no labored or rattled breathing, no sneezing or vomiting. They just stand there with their tail and wings hanging low and their feathers poofed. They don't walk around and they don't eat or drink. They eventually sit down and later lay down to die. It is sad to watch this knowing there isn't any thing that I know to help them.
I started all of these chicken on a medicated baby chick crumble for the first two months. After Christmas, I changed their feed to an organic meatbird feed with about 22% protein. About three weeks ago we began feeding this feed once in the morning and allowing them to roam the property and free range. They get locked up in their house at night away from preditors. They have free choice of fresh water all day long.
The other thing that has changed at our small farm is we purchased two dairy goats (they are presently dry) two weeks ago. We do put everyone up in the same area each night. Everyone is cohabitating together just fine with no signs of stress or aggression. Everyone is also fed seperately and supervised.
The other consideration we have is we have not gotten around to a deworming regimen for the chickens since we began free ranging them during the day, yet. It has only been a few weeks and it is winter here in central North Carolina. It was recommended to us that we deworm our flock every three months. Our flock is currently about four months old.
If anyone has any suggestions as to what could be happening either "kttodd" or my chickens, I think we would both be very appreciative!