Hens are mixed layers, RIR ect. 15 hens and two roosters 1 rir and 1 grey. About 1 1/2 years old. three weeks ago switched feed to natural Kelly's for layers. There has been evidence of a rat? in the hen house. Two days ago in the am I found one hen in the hen house dead. no signs of injury or illness. Today found 4 dead? again no signs of illness or injury. Wierd they molted in the winter and are now getting nice and full and pretty. The feed switch started three weeks ago and the beging they layed 22 eggs in one day and twice the normal size. Sounded good so we switched out to full Kelly's starting two weeks ago. This am the flock was not excited to eat they did but not excited like normal. (Might be upset of so many friends dieing)? I really am upset and want to fix this fast. What should I do? I am first time flock owner and am sickened that i am making mistakes and the birds are paying for it somehow??