All my chickens died overnight for no apparent reason

[SunHwaKwon]

So one hen and her chicks survived? If the chicks are alive, I would rule out gas poison as they would've been the first to be affected.

I'm really sorry about your losses.

That depends on how dense the gas is and the position of the mama and babies relative to the rest of the flock. Some gases stay low and some go up high.

 

[slippednfell]

That was the factor that made me think it may be a poisonous gas. At a different height chickens did not die. Gas can accumulate at one level but not the other. There is some sort of Ancient story about this in Egypt I believe, may even be a biblical story. The eldest sons of every household died because it was custom for the eldest sons to sleep in a higher position. The poison that killed them was from sort of Geological phenomenon. I vaguely remember the story and the specifics.

Thank you for the correction! Actually I was just coming back to negate my post... if the chicks were under the hen, that would explain how they were spared and if CO2 rises and the hen was lower, I would be totally wrong.

 

[Northern Flights]

That all did not perish is very significant imo, almost totally ruling out gassing or nasty neighbours. Almost...

 

[Kiki]

I'm sorry for your loss.

Can you post pictures of your coop?

 

[SunHwaKwon]

That all did not perish is very significant imo, almost totally ruling out gassing or nasty neighbours. Almost...

I think it makes it even more likely. A predator would be more likely to notice the mother and babies, whereas a human (especially one who is not chicken savvy) might not think to check corners, nest boxes, etc for others who are not on the roosts. And the way gases work also fits the scenario. Think about how in a fire they tell you to stay down near the ground because of the smoke and CO. With Cl, on the other hand, it stays down near the ground so you are better off up high. It all depends on the gas and its density.

 

[Compost King]

Thank you for the correction! Actually I was just coming back to negate my post... if the chicks were under the hen, that would explain how they were spared and if CO2 rises and the hen was lower, I would be totally wrong.

CO2 is actually heavier than Oxygen (not sure about Nitrogen)... but we do not even know it was a gas issue let along what gas.

 

[cheeseheadken]

Were all the ones that died up on roosts, and the mama and babies down near the ground?

Correct - mama and babies on the floor, the rest roosted. The house is raised on a platform 2 feet off the ground.

I don't believe they were purposefully poisoned. I live on 11 acres and the drive has an alarm. Don't think I've ticked anyone off lately either!

Thanks for your thoughts!

 

[EggSighted4Life]

Just baffled here. Unlocked the henhouse this morning and every one of my 11 layers (except one who had hatched some chicks, and her 5 chicks) was dead in the coop, apparently unharmed. No feathers missing, no blood, no wounds, nothing. The only thing I can think of is they were poisoned somehow. Spoiled feed? I've seen chickens eat a lot of crap...literally, so I'm not sure what would otherwise have killed them. Any suggestions?

So sorry for your loss.

Please tell us what position the bodies were in when you found them? Did it look like they fell off roost, piled in a corner, individually random places? Sorry for asking, details matter.

Any chance it's those nasty buffalo gnats that have wiped so many flocks out this year?

Hope you get answers.

 

[cheeseheadken]

Did you have spike in temperature yesterday?

nope - we've consistently been in the 80s/90s all summer!

 

[slippednfell]

CO2 is actually heavier than Oxygen (not sure about Nitrogen)... but we do not even know it was a gas issue let along what gas.

I understand we aren't sure if it is gas or not, but my first (and incorrect) post was trying to rule out gas. Thank you for the correction on CO2 being a heavy gas. I have no more to contribute to help solve the OPs question, so I will excuse myself from this thread.