I just did another post, as I have 6 chicks about 2 weeks old and one isn't doing well, suspected coccidia. They were vaccinated and I've been feeding medicated feed, and on here it says that will void the vaccination. So now what? Switch to unmedicated? Treat them for coccidia? Only one is showing any (possible) symptoms - she's weak, listless, not growing like the others. Should I treat just her or all of them?