I have five 11 week old chicks (golden comets) who have been out free ranging with my older flock of chickens for 6 weeks now. I just noticed a round worm in one of my year old australorps poop and will be going through the piperzine first/ivermectin 2nd regimine with them. Are the teenagers old enough for the piperazine or do I need to seperate them? My plan is to give the older ones 1 ounce of piperazine per gallon as their only water source for 24 hrs then remove and treat again down the road with pour on ivermectine. Can the teenagers do the pour on ivermectine? I also have some 4 week old babies - still with their mom (Mom needs worming also) in a seperate pen. Do they need any treatment? Any help would be appreciated.