Help! Heat and seizure Cornish cross

[Wyorp Rock]

We just lost a Cornish cross hen tonight. She was our biggest and grew much faster than the other three. We got them all March 31st. . They have been on organic start and grow feed and have been getting amprolium in their water. Our big girl was super active up until about 3 days again she just quit walking and stranding. He legs were like tree trunks so I do not believe her weight had anything to do with it. We moved food and water close to her since she was not moving..she was eating so we kept her out side two days before we noticed she had stopped eating. Once she stopped eating we brought her inside. We started using a dropper to give her water and tried our best to get food in her.. crumble, Broccoli, meal worms..she was so weak she would fall asleep with her beak in her water..she would not move at all just hardly lift her head and didn't keep her eyes open long at all. He poo was mostly clear..when she was outside it was mucus mostly. We moved her to change the bedding under her and then sat her back down and tried giving her water tonight and it seemed like she had a seizure. All of our other chickens are fine.. could she have had a heart problem? Did she maybe have a heat stroke outside? It was pretty hot a few days before close to 90.. the way she grew kind of makes me think maybe her heart.. but I'm not sure...we are new to this.

I'm sorry for your loss.

It would be hard to know what caused her decline without necropsy. Meat birds can have several issues since they are meant to grow quickly and most are processed around 8 wks. Heart failure is something to consider. If you are up to it, you may want to take a look at her organs just to see if you find anything off.