I have a flock of 20 birds and they seem to be starving even though there is food in there at all times, I am loosing about a bird a day and today I noyiced two more look sick. I am not new to pigeons, I had a large flock when I was kid. Never saw anything like this. Some of the birds are new to me. One is a stray racing homer that stayed with my birds, she seems healthy. Ideas??