My friend Nathalie Ross "threehorses" put this on one of her posts on worming
Time to evaluate your whole flock. Pick them up, check their keels. If you feel sharp keels, it's time to consider your worming protocol. If you haven't wormed in a while, then worm first with piperazine to knock back the majority of roundworms, the most common worm in poultry. It won't kill them all - and that's good. If your birds are heavily infested then you only want to kill a good number and not all so as not to overwhelm your birds' systems with dead parasites. Overwhelming could include rejection of the foreign proteins which the dead worms become, or clogging of the intestines with the passage of dead worms. So piperazine first, wait a bit, then either do it again or go with something more strong like ivermectin or another broad-spectrum wormer recommended here.
Any time you treat with anything, including wormers, you should always use probiotics thereafter in the following week. These can include store bought livestock probiotics like Fastrack or Probios, avian specific ones from
Petsmart/
Petco like Ornabac, capsules of acidophilus (or yeast-infection treating pills) from the grocery/health food store/pharmacy, or even plain yogurt with live culture (most are). Mix whatever probiotic you choose into something you know they'll eat quickly - wetted down crumble with egg yolk is generally irresistable.
with that said for round worms
I will post the next one on Ivermectin
about using Ivermectin for the other worms