Chick Dilemma - Coccidiosis/Treatment ????

[Brahmadarma]

My dilemma is this - I bought five chicks from a feed store, they are now 3wks and 5wks old.
I have just added a week old chick from another feed store and this one was vaccinated against cocci.
Blood is just beginning to show in the poop, but it looks like it might only be one bird from the number of red feces.
I have read that you should not medicate a vaccinated chick or the immunity will not develop. It could be just this little chick and its the first signs of the disease from the vaccine.
I want to give them Sulmet as a precaution. I don't want to let it spread and leave it too late.
It seems almost pointless to have only one chick vaccinated anyway when it is such a contagious disease.
What would you do? I am strongly leaning towards medicating - now, before they get too sick.
Can anyone help please?

 

[beakkeeper]

Do you know for sure that it is the vaccinated bird that is getting the bloody poo? It could be that the others have caught it from that one and now they are sick. Separate the vac. one and give the rest Sulmet or Amprolium.