I had four pigeons, which I got about two weeks ago. They all were doing fine until one of the pigeons got into some All Flock feed and ate a lot. After he had eaten so much, every time he drank he would tip back his head with his beak open, and sometimes stretched his wings at the same time. After 4-5 days of being like that he died, I found him on the floor with his legs back and his head bent backwards, I picked him up and after a few spasms of flapping he died. The other three seemed fine until yesterday one more pigeon starting being just slightly inactive. She didn't quite land perfectly, and she seemed to not be flying as well. Then this morning she was found dead in the same position. She never got into any food she wasn't supposed to though so I don't understand? We feed them 1 tablespoon each of a mix of wild bird seed, cracked corn, and Purina All Flock, along with plain grit in a separate container. Is this a disease or is it something we are feeding them?