I have 11 hens I need to worm and was wondering where I would get it and what types are out there? Is there something I can put in the feed? or water bowl? They seems they have loose stool and I have never wormed them. I have only had them for about three or so weeks. Before that I got a straight run of 6 RIR's and ALL turned out to be roo's so I got these girls instead. They are about 9 months old. Thanks in advance!