Our broody hen has just hatched 3 chicks in the past 48-24 hours. We just gave one chick the mareks vaccination and it went all wrong. I gently held the chick while my husband gave the injection, .2 ml subderal using a very small needle (a TB needle/syringe) as we saw in a youtube video. Immediatly afterwards the check displayed neurological symptoms, right sided weakness, inability to stand. My husband is a nurse and insists he gave it correctly. Has anybody else experience such a thing? We were so saddened by this we did not continue vaccinating the others.