Even if vaccination did cause us to lose chicks in the egg it would still be worth it, because all of the chicks that I vaccinated in the egg last year are still alive as productive hens! We also just had a big round of euthanizing for Marek’s in our unvaccinated two year olds. I don’t know if you remember Susan, our silkie who was doing poorly after the death of her showgirl clutch mate to Marek’s last year? Susan is the one we rushed shipped chicks to when her clutch of marans eggs failed to hatch last summer? Susan was one of those three. I console myself by saying that we bought her another year, and it was a happy year. She was a fantastic mom! Gratuitous pics included because I loved and miss Susan.
Anyway, I’ll continue vaccinating, but I may try to adjust my technique a little. The more I’ve pondered, the more it seems to me that I injured that chick, since it’s yolk wasn’t absorbed and the broken vessel was where I would have injected. It’s funny how the commercial in ovo technique is reported to injure almost no chicks. I’m wondering if vertical vs horizontal incubation plays a part in that, since it affects how the air cell is oriented to the chick.