my birds healthy
It does no harm whatever to add vitamins to your flock's water every now and again. I do it every month or so just as a matter of course - giving their immune system a little helping hand is good practice IMO. Evidently others may disagree, and thats fine since we all do things differently - very few rules when it comes to keeping chickens!
All the best
Honestly not too sure but i would have thought its fairly generic - the vitamin supplements for chickens here here in Kenya is also used for goats and other livestock, so I would not sweat it too much.