Diseased chicken and malformed eggs

[DrTheMomm]

I have four Cinnamon Queens. I had five, and one of them was laying malformed, incomplete eggs. Then one of them died, and we stopped getting those eggs. Now we are getting them again, and one of the girls is losing her tail feathers, and she has a bare butt. She looks diseased, and we think she's the one laying the bad eggs. We've isolated her from the rest of the girls to see what happens. If she is diseased, is there something we can do to help her?

 

[nuthatched]

How old are they?
Diet?
Coop size?
Any other symptoms?

 

[DrTheMomm]

How old are they?
Diet?
Coop size?
Any other symptoms?

They're about one year old. They have a 4x6' bunkhouse that they sleep in. It's attached to a run that's probably about 10' long. (I'm not positive; my husband built it.) So they're not confined to a coop all day. Some days they free range on our land. They eat chicken pellets, a local brand. I've tried adding oyster shells in their feeder, but they won't eat it. I put ground up egg shells in, and they might be eating that because it's harder to pick out. No other symptoms. And they are about one year old. Also, I forgot to mention that we're in West Texas, where it is very hot.

 

[DrTheMomm]

Here are the correct dimensions: The footprint is 8x16'. That is the dimension of the tractor. The bunkhouse is on top. It is 2x2x8. That's where they sleep at night.

 

[LaFleche]

Please, post a picture of the malformed eggs.
Infectious Bronchitis (a virus) is known to cause malformed eggs.

Infectious Bronchitis in Poultry - Poultry - MSD Veterinary Manual https://www.msdvetmanual.com/poultry/infectious-bronchitis/infectious-bronchitis-in-poultry

 

[LaFleche]

How well is their coop ventilated?

A picture of the coop would help to determine if the ventilation is sufficient.