What is this?

[Ted Brown]

I found a dead hen today. Any help identifying what this is greatly appreciated.

 

[Wyorp Rock]

Is the poop frozen on there?

Hard to tell what's going on. Perhaps she had a stuck egg or soft shelled membrane and it froze blocking the vent?

If you are up to it, more photos may be helpful and opening up the bird to take a look at the internals may reveal more.

 

[Ted Brown]

Yes frozen. We got to -30C overnight; late for such low temps.

I will take more photos. My principal concern is the rest of the flock; I go in after dark tomorrow and have a quick look at as many hens as I can. Then will think about next steps.

I have had a hen only flock in the coop/run for many months. Put a Chantecler roo in 5 days ago; half of the 24 are Chants, the hen that died was a Barred Rock.

 

[Wyorp Rock]

Yes frozen. We got to -30C overnight; late for such low temps.

I will take more photos. My principal concern is the rest of the flock; I go in after dark tomorrow and have a quick look at as many hens as I can. Then will think about next steps.

I have had a hen only flock in the coop/run for many months. Put a Chantecler roo in 5 days ago; half of the 24 are Chants, the hen that died was a Barred Rock.

I understand your concern. Hopefully you can figure this out and the photos will show more.
I think perhaps she may have had a shell-less membrane or stuck egg. It's hard to tell though.