We ordered 75 chicks from Meyers hatchery and had all of them vaccinated for merecks. They are now 8 weeks old, and one of our white rocks is incredibly wobbly and can barely get around. She is still eating normally, but closes her eyes a lot. No one else is acting like this. Even though she was vaccinated, could it still be merecks? I am so so worried about the rest of the flock if it is... any help or advice would be very appreciated!!!