I have zimectrin gold. Use a BB size to give to your chickens,it's very potent stuff. It'll also kill tapeworms, but I prefer to use valbazen as an all around wormer after using wazine. I've used safeguard as well as ivermectin pour on as second wormers and rotate among the second wormers to prevent worm immunity to one particular wormer. You should wait at least 2 weeks before using the second wormer. Wormers are rough on their systems and about 2 days after use of wazine as well as the others,you should give your chickens yogurt mixed with canned beef catfood and scrambled egg mixed in with their feed to make a mash.(dont use eggs layed after worming) you must throw all eggs in the garbage for 2 weeks after wazine, 2 weeks after 2nd worming also. Giving them yogurt etc...will build up their immune system and the extra protein will bring their strength back.