Woke up to hen and chicks dead, no sign of injuries

[piXelsbite]

Hello.

We have a secure enclosure of... 6mX6m. We keep 2 hens at a time inside, each with their own cage to sleep in separately. There's no way for any predators to come inside. They eat and drink from the same places and interact with each other daily.
This morning, our hen with her 2 week old chicks were all dead. I've looked at the bodies but there doesn't seem to be anything wrong with them. 5 of them were under/next to the hen, the 6th was outside, also dead. I have no idea what could've happened. I made a picture but I'm not sure what seeing some dead animals would help with. I'll update it on request.
The other hen and her approx 1 month old chicks are alive and behaving normally. Nothing is wrong with any of the others, which only confuses me more because they live in the same space. I'm very confused.

 

[Wyorp Rock]

I'm sorry for your loss.

Can you post some photos of the housing/pens?

 

[piXelsbite]

Not s

I'm sorry for your loss.

Can you post some photos of the housing/pens?

Not sure if it shows anything relevant, but here. The cages are old cages too small for our dogs to use, hens seem happy with them. We've kept hens and their chicks for 4 years now in here and nothing ever happened. Except when the chicks were stubborn and insisted on escaping...

 

[Wyorp Rock]

I would be looking for where something either got in and disturbed the hen/chicks or something on the outside that startled them badly.
Do you have a game camera you can put up to see what's coming around?

Since they are in the same run with same food/water during the day and the others are fine, I would make a guess that the cause was a predator.

 

[humblehillsfarm]

Any chance at all they could have ingested something poisonous? Any signs of bite wounds maybe from a snake or spider (no idea if spider bites are possible). What was the temperature? I'm so sorry for your loss! I hope you can get some answers.

 

[piXelsbite]

I would be looking for where something either got in and disturbed the hen/chicks or something on the outside that startled them badly.
Do you have a game camera you can put up to see what's coming around?

Since they are in the same run with same food/water during the day and the others are fine, I would make a guess that the cause was a predator.

We've thought of it too but the enclosure is double crated, sturdy wire so nothing can get in and very fit net so the little chicks can't get out. The hen was inside one of the cages when we found them, with the chicks under her, which makes me believe they died in their sleep. If something did get in, then why not eat them or kill everyone as opposed to just one hen and her chicks? There's plenty other chicks in there.

 

[piXelsbite]

Any chance at all they could have ingested something poisonous? Any signs of bite wounds maybe from a snake or spider (no idea if spider bites are possible). What was the temperature? I'm so sorry for your loss! I hope you can get some answers.

Bodies look fine. The only thing that's amiss is that they're dead. My father thinks they might've been poisoned with gas but that makes no sense to me. There's no gas source around and it should've killed everyone, not just them.

A spider bite wouldn't be noticeable but each and every single one of this batch and no one else?
I ventured to think that the hen died for... reasons and the chicks couldn't keep warm during the night so they died too. But it's summer and it's pretty damn warm during the night and they were already between 2 and 3 weeks old. Surely old enough to survive alone for one night? I have no clue.

 

[humblehillsfarm]

Bodies look fine. The only thing that's amiss is that they're dead. My father thinks they might've been poisoned with gas but that makes no sense to me. There's no gas source around and it should've killed everyone, not just them.

A spider bite wouldn't be noticeable but each and every single one of this batch and no one else?
I ventured to think that the hen died for... reasons and the chicks couldn't keep warm during the night so they died too. But it's summer and it's pretty damn warm during the night and they were already between 2 and 3 weeks old. Surely old enough to survive alone for one night? I have no clue.

I wouldn't think at that age they'd die so quickly without their mother's warmth, and besides, they'd still try to be under her and she would still give off warmth for a short period.

 

[piXelsbite]

I wouldn't think at that age they'd die so quickly without their mother's warmth, and besides, they'd still try to be under her and she would still give off warmth for a short period.

Probably

 

[LaFleche]

Did they look quite pale? They might have been victims to a nocturnal mite attack.

I would inspect the hut closely, even take it apart to see if there is any infestation.