Why do my birds keep dying???

[Bigzmey]

Help!! I’ve been raising chickens for 8 years, never had a problem. Sure, the occasional bird would die now and again but it was a rare occurrence. I’ve lost 6 over the course of 3 months (maybe a little more) and I can’t figure it out!! A few were some of our oldest, but half of those were not even a year old! I even had one autopsied and cause of death wasn’t found. the only thing new is the new birds, and a new coop. I did notice recently when the rain started that there’s a leak over the nesting boxes I’ve been trying to fix and trying my best to keep bedding dry. I use hay. All bodies had good meat on them, clean vents, autopsy clear..... whats happening?!?

edit to add: I do have rats, have for many years. Could it suddenly be disease from them?

Did you make any changes 3 months ago? New brand of feed or scratch? New bedding? How well is your new coop vented?

 

[black_cat]

What's the mill date on your feed?

 

[jolenesdad]

Do you have a copy of the necropsy findings? Did they suggest histology? Birds can be clean on necropsy but riddled with issues at the cellular level when histology is performed in tissue samples. It’s usually a 50-100.00 addition after a necropsy.

which bird did you have necropsied? Old or young?

 

[Trisseh]

Sorry to hear you’re losing birds. It’s so frustrating.
I second every suggestion of additional necropsy, but add that if you have multiples, it’s usually better to send all dead around the same time to get a better picture on the lab’s end. And definitely give them a call and as thorough a history as you can. Gross necropsy won’t necessarily tell you much if the cause is viral or any other host of things as @jolenesdad mentioned. Histo and PCR testing for common pathogens/diseases may be the only way to get answers.
I had ducklings die this summer from leucocytozoonosis. I had to call the lab and confirm because it was the first time I had heard of anyone in this area having it; the necropsy was pretty routine, but the birds were pale and they did a blood smear and confirmed. Sometimes further diagnostics are necessary.