I am not familiar with Vetrx...from what I gather it is nothing more than a Vick's Vab-o-rub type thing.I'll put her back then! I have some VetRx on hand do you think that would help at all?
Is it dusty in your brooder?
I am wondering if you might have been sold sick chicks.

Could be the beginning symptoms of MG.
Does your feed store carry antibiotics such as Tylan?