About six weeks ago, we had several chickens with tapeworms. -dosed with Zimecterin Gold, waited 10 days, repeated. All were clear.....until yesterday. Two of our nine have them again. These chickens have the cleanest environment! -coop is cleaned daily, run is scooped three to four times per day. -attempt to keep everything nice and dry, also. They do have access to the lawn three to four times per day, and do occasionally suck down the earthworm, beetle, and ant. (We have tons of ants in this area of North Texas...) I have given the two affected Zimecterin Gold again. -am concerned, however, that giving this so frequently (if they keep getting reinfested) will not be good for them or cause some sort of resistance to the wormer rendering it ineffective in the future. Help!!!! Are tapeworms really this common??