Lessons with Chichens

I have mostly raised my chicks from a few days old and once bought some grown chickens and never have a problem. I had been in touch with a local breeder about her Heritage delawares and wanted to try they out. I called her and she said she was selling the last of her 3 month old birds. She had about 16 left so I called a neighbor and she wanted a few, so we acquired them on a Sunday. I did notice that when I brought them home , one had a drippy nose, but I did not think about it. About a week after I let them in with the others, my original flock started coughing , eyes swelling and not eating.
I used Colloidal Silver and it was working, but I ran out before the run was complete.I switched to Met-sul, But it was not the right med, so I put them on LS-50, which worked to a point. As soon as I received my Silvonic colloidal silver generator, I was able to make enough to put it in their water on a daily basis. When I sprayed it into their eyes the film cleared and the chickens could see again.
What they had was a condition called Chronic Respiratory Disease  AKA  CRD. The Heritage chickens were carriers that the women I bought them from denies they were sick, but our friends who took a few had the same problem with their chickens. When Chickens are sick they stop laying as well. During the rounds of antibiotics I did give them The Silver in the water and they now show no signs of sickness but they have dropped in egg production by half ( I am writing this June , 9 2013).
I am seeing who are the layers one by one putting them in an isolated cage . We will see after the experiment is over.