She gives you a dose in this above...for the vitamin. I think you missed the last part.I read that Covenia is not recommended for use in birds because of the incredibly short 1/2 life. I think this is mentioned in one of the two links I posted.
Anyway, sounds like you've tried a things. Can you try giving the rooster booster orally instead of in he water?
If your vitamin bottle is like mine, and you were to follow the max dose of 5 ml/100 pounds, you could probably give her 0.25 ml very safely. Use of this drug in poultry is not documented, so that's why I'm hesitant to say "oh, just give x". I personally have used it in a few at 0.25 ml per pound.
