I have ten chicks that are 4 wks old. Six were vaccinated and four were not. One of the four got sick yesterday and just slept all day with mucus-like poo. I also noticed she is smaller than other 9 chicks. So I bought some Sulmet this morning and gave it to her. I would also like to give the other three that are not vaccinated the treated water since they have now been exposed to the protozoa for at least a few days, even though they're not showing any signs of the Cocci yet. I would really rather not seperate the four from the other six, so my question is will the Sulmet harm the vaccinated ones in anyway? I understand it will counteract the vaccine, but I didn't pay extra for it anyway. Plus, I also understand there are 9 strains of Cocci, so unless they were vaccinated for all 9 strains, they could still get this strain. Correct? SO...just want to make sure it won't harm the chicks by doing this. Another note: the guy at our local feed store tried to tell me there is no vaccine for Cocci, because it's a protozoa and he told me to treat all 10 of them. I don't think he knew what he was talking about, but maybe I'm wrong.