Hi Janine, We use the Frontline for Cats, They sell them in packs of 3 or 6, They are all the same size vile. but you only need a small amount for each bird.....Our Chickens are large and are 4 years old, and we use the same amount on all of them, you dont need a lot, just the amount I said, approx
2-3 drops from a dropper syringe, part their feathers on the back of their neck and apply. One of the chicken breeders who uses it takes her stuff to a vet and he waters it down for her, but we have always just applied a small amount directly on to them, either way is ok.
Yes it gets into the chickens skin, so when the mites, or lice feed on them it kills them. I don't think it gets into the bloodstream, we have used it for a long time now, we eat our eggs (we don't sell any) and we are mite free (only joking) we are all fine. I guess if it was a problem the Vet would have advised the Chicken breeder not to do it, and he recommended it too!!! - If you need any more info let me know - regards Marianne