2 dead and another looking bad

[Bugman37]

I had one of my chickens die 3 days ago. She seemed lethargic and you could tell she felt bad. She was open mouth breathing and just lying around, wouldn't eat or drink. I found another one dead this morning, but she didn't show any signs of distress yesterday. Also another of my hens is now showing signs like the first hen. I'm going to put some antibiotics in the water to help the others since it seems to be contagious. Any other ideas??

Thanks,
Charles

 

[FlyHigher]

How old are they?
Are there any neurological symptoms?

 

[Bugman37]

They are only 2 years old. The only other "symptom" is that they haven't been laying like they should the past couple of weeks. I had 6 hens and was only getting 1-2 eggs a day. Everyone said it was probably the heat even though it's only been 85-90 here. I thought that the first one had not been able to pass an egg or something, but now this morning with 1 dead and one struggling I know it's contagious,