Sick hen pheasants

I have had an outbreak of dead pheasants in the last 3 days. It is only affecting the hens in the pen. some of their eyes swell shut and then they die. They seem to act drunk or stumble around. Then they just drop dead. But it is only affecting the hen pheasants. I think I can rule out the feed as I feed the same thing to my chukars and chickens and i have had absolutley no problems with them. I have treated their waterers with Terromyacin. It doesn't seem to help. At this pace i'm gonna lose my breeding flock in about a week. Any suggestions would be greatly appreciated.

Also noticed some seem to have the runs. I also noticed when I picked up one live bird that looked sick to get it out of the pen it threw up.

help please

If anyone knows what this is you can also email me direct at Royalflushpheasants@yahoo.com

Thanks,
Curt