My hens have been vaccinated for coccidia. They are 7 months old. They all were healthy up until about 2 months ago. I noticed one with blood by its vent. I took her to the vet and he prescribed baytril at a dose of 0.5 ml once per week claiming that it is a very powerful drug that should kill anything. He did not know what specifically was wrong. He also took a stool sample and nothing came back abnormal. A month later "her vent area exploded" . It was horrible. Today, another chicken "exploded". Something is terribly wrong and I need help. Has anyone experienced this and can you provide me with direction?
I have another coop with older chickens and they are fine.I have never experience this problem before and I don't know how they got this disease or how to prevent it. They eat the same feed and I provide the same water source for them. The coops are about 50' apart.