What am I doing wrong?

[HeyHey]

I have had this happen 5 times in 2 years. I raise the chicken all different hardy breeds until about 7-8 months old then they get sick and die.
They free range in a fenced area, are my pets, have clean everything.
Some I have had the whole time and are fine?

 

[FunClucks]

What are the symptoms they get when they are sick? Do they all get the same symptoms? how long are they sick before they die? Diseases like Merek's can stay in the soil almost indefinitely, I suspect you have one of those. No idea which without further info. If you raise more chickens, and they get sick and die again, recommend sending at least one off to have it autopsied. Metzer hatchery has a list of state labs in the USA where they can perform an autopsy. Follow the lab's instructions for body storage and shipment to be sure they can get the info you're requesting.

Have any of the chickens/chicks you've had been vaccinated for anything? That might account for them being fine - they may have the disease, but not succumb to it, and are carriers for the disease and infect your newly raised chickens. Many chicken vaccinations only make the affected chicken not succumb to the disease, they don't cure the chicken, or prevent it from passing the disease to other chickens.

 

[HeyHey]

What are the symptoms they get when they are sick? Do they all get the same symptoms? how long are they sick before they die? Diseases like Merek's can stay in the soil almost indefinitely, I suspect you have one of those. No idea which without further info. If you raise more chickens, and they get sick and die again, recommend sending at least one off to have it autopsied. Metzer hatchery has a list of state labs in the USA where they can perform an autopsy. Follow the lab's instructions for body storage and shipment to be sure they can get the info you're requesting.

Have any of the chickens/chicks you've had been vaccinated for anything? That might account for them being fine - they may have the disease, but not succumb to it, and are carriers for the disease and infect your newly raised chickens. Many chicken vaccinations only make the affected chicken not succumb to the disease, they don't cure the chicken, or prevent it from passing the disease to other chickens.

Some have been vaccinated and some were hatched here at home.
They get weak have trouble with balance and die within 3 days.
I have wormed them and treated for cosicosis (sp)

 

[FunClucks]

Some have been vaccinated and some were hatched here at home.
They get weak have trouble with balance and die within 3 days.
I have wormed them and treated for cosicosis (sp)

I suspect Merek's, but I'm sure there's other possibilities. Avian influenza, lymphoid leucosis, etc. When it happens again, send a bird for autopsy. Just no other way to say for sure what's going on. Sorry you're dealing with this.

 

[Eggcessive]

Sorry for your loss. Do you have chickens right now that are acting sick? Are they able to walk, or is one leg weaker that the other? What do their poops look like when they are sick, normal and formed or runny, yellow or with any blood? Have you ever treated with Corid for coccidiosis? Is there any mold in the feed or treats? What kind of food do you feed your chickens? What state are you located? Most state vets with do a neceopsy/autopsy on the body of a chicken if you lose another. Keep the body cold, but not frozen and send it to them. Here is a list of state vets to contact and how to keep the body:
https://www.metzerfarms.com/poultry-labs.html

 

[Crazy Chicken Boy]

I suspect Merek's, but I'm sure there's other possibilities. Avian influenza, lymphoid leucosis, etc. When it happens again, send a bird for autopsy. Just no other way to say for sure what's going on. Sorry you're dealing with this.

I would agree with your Merek's diagnosis. I had a similar thing happen with my hens and now I just always get them all vaccinated.

 

[FunClucks]

I would agree with your Merek's diagnosis. I had a similar thing happen with my hens and now I just always get them all vaccinated.

Merek's is a hard thing.

There's so many other things it could be for the OP, but IMO Merek's is likely. I hope OP answers Eggcessive's questions though, it could be something else that's fixable/treatable that has been missed.