Q Should I be vaccinating against mycoplasma? If I have a flock that has had suspected mycoplasma in the past, would it be safe to add vaccinated chickens into the flock? A Victoria says: Chickens vaccinated against mycoplasma do not seem to pass it on to naïve hens. The mycoplasma vaccine merely lasts six months, if that, so is not really economical or practical. The disease itself is very contagious and wild birds can carry it, (another reason to keep hens and wild birds separate). Treat the new hens in quarantine with Tylan Soluble for five days plus the old hens if they are showing symptoms. I medicate and control it by using Tylan Soluble at the first sign of snivelling. Not forgetting to dissolve the 1g of powder first in a small amount of water by vigorous shaking in e.g. a pill pot before adding to the 2L water, otherwise it sits on the bottom of the drinker and does nothing.