chicken lethargic, seized and died

[Leavingegypt]

I moved my "teen" chicks (2 Buff Brahmas 2 Partridge Rocks 8wks old) to a new temp location underneath my existing coop. It's a 2ftx8ft run area that we just put a door on. We needed to move some younger chicks to the tractor the teens were located in prior.
The 4 seemed to be doing great, lively, eating and scratching. They have been in there 3 days. Today I came home to see 3 of the teens scratching, pecking and generally doing chickeny things, but one was "napping". I went in to get some snacks for all the chickens. I fed the adults first then went to the teen birds. The 3 were very happy for treats, but the 1 Buff Bramha just stood up a little and then laid back down with her eyes closed. I reached in and picked her up. She opened her eyes, but didn't really move much. I tried to give her water, but she didn't open her beak much and didn't drink. I set her down and she immediately began seizing and died.
I saw no injuries and the other birds seem fine. It has been warm today, about 80, but the area is in mostly shade. I had put the water up from the ground at first, but wondered if it was too high, so I put it back on the ground yesterday. What happened in just a matter of 6hrs? Also the feeder and waterer came out of the run they were in before so I don't think that would be contaminated.

 

[Leavingegypt]

I have had all the birds since they were few day old chicks. No new birds have been brought into their group and the run has been in it present location for a year. Prior to us putting a door on that portion, it has been open to the adult chickens- although they seldom went in there. I have never had a chick or adult bird die of anything other than a predator attack and a roo died after running into a post and breaking his neck.
Should I b worried about the other birds? Should I take them out of the area they are in?

 

[wbrr2009]

My chicken just had the same problems. I went outside and she was laying down, I went into the coop and usually if I come within a foot, they will run a little but this time, she didn't do anything. She just kept laying there. So I picked her up and noticed there was clear red liquid on her feather near her rear (watery blood). I put her near water and she wouldn't drink. I read up and thought maybe she had an egg stuck, so I put her lower half in warm water and rubbed her belly from front to back. I put her in a towel, wrapped her up so she wouldn't get cold. About 10-15 minutes later, she had a seizure in my arms and passed away. This just happen about an hour ago. I think it was eternal bleeding maybe? I don't know.

 

[ernie85017]

Do you have any rat poison around? The blood reminds me of that kind of death. FWIW