The nineteen chicks of 49 were a shipped in order vaccinated for Mereks and shipped from a NPIP and certified mycoplasma free hatchery. But they started dying immediately. The Welsummer is the only one of my chicks to die, and she was fine prior to me boxing the six up and taking them out to the coop that has the seven from Christmas. That is just odd.
Is it possible to over dose a chick with the Mareks vaccine? When my friend helped me learn to vaccinate I don't remember him telling me it was possible but there was a certain dosage needed to work. I do remember my chicks looking very sick after the dose. Couldn't image having to ship them anywhere.
Ask the hatchery if they had other problems with this hatch? Maybe there was a new employee that did not know proper handling.
Or we are dealing with the post office. Did they get to cold during shipping. What was the weather like when shipped. How many days to get to your chicks
As to the Welsummer I don't have any ideas except to say I've lost three of my NY HAL chicks. I'm certain they are the ones I helped. No more helping my hatch I'm afraid.