With the Panacur 10% you dose each bird individually, by mouth, which if you have alot can be time consuming. The ivermectin, which I haven't personally used, is just dropped onto the skin. This wormer is apparently not as good at worming but if you get one that has an insecticide in it, gets rid of mite, lice and fleas. I was looking at one called Eprinex. It's licensed for cattle but I do know a few poultry keepers that use it on their breeding stock. I wouldn't use on birds to eat and it would be sensible not to eat the eggs for a while either. The Panacur 10% is similar to flubenvet and is used for small animals, cats and dogs etc. And you can get it in 100ml bottles, great for smaller flocks. I just followed the dose rates on the bottle for dogs and re-calculated for chickens. I will try and get hold of the chap that uses the ivermectin one to find out exactly what make it is.