I vaccinated my batch of 3-4 week old chicks last friday for new castle/bronchitis. They were all ok until monday night. I was gone for three days (someone was looking over them) and when i came back tonight a bunch of them were sneezing a bit, and had one runny eye (only one eye runny... not sure if those are where i put in the drops). So they seem to have developed symptoms 5 days after the vaccine. they are all eating/drinking/otherwise active. Is this normal? i can't really find a lot of information on this. i gave them vetrx, not sure what else to do. any thoughts please let me know.