I have a welsummer chick (3.5 weeks) that is doing this as well. I got on here to look for answers. My chicks have only been in their box since I got them. I have five others (1 other welsummer) and all the others are fine so far. I have been giving them water with chick boost in it every day since they were a week- it has riboflavin in it as well as elecrolytes and probiotics and other vitamins. Could it really be a vitamin deficiency?
I have seen a couple other posts that mention something like this in welsummer chicks. Are they susceptible to this?
I have a hard time believing it is Mereks, but maybe I just don't want to believe. Where would she have gotten it? I will have to talk to the store where I bought them to see if they were vaccinated. I did not ask at the time. I have 5 older chickens that are out in the backyard and I have never dealt with this before.
My chick is also very interested in food- especially high protein like yolk, yogurt and mealworms. Poops are a little wetter than the other chicks, but still solid. She can barely balance when she is on her "knees". She moves like she is dizzy.