Downed Cornish cross

[BakersBluffFarm]

I have a Cornish cross hen that went limp today. It's not that she's too heavy to move, but her legs and wings have stopped moving, doesn't really move much if I turn her upside down. Very lethargic and unwilling to eat or drink and is breathing heavy. This just started today and none of the other meat birds I have are doing this.
Anyone know what may be causing this? Wanna nip it in the bud so my other birds don't have any issues if it's transmissible

 

[Eggcessive]

Sorry about your chicken. Can you also post this on the meat bird thread here:
https://www.backyardchickens.com/forums/meat-birds-etc.21/

I don’t have experience with meaties, but I would,
try to get it drinking some fluids with electrolytes. Some meat birds can suffer heart attacks, and if it is hot where you live, there could be heat stress. I hope others will help you.