It depends on what you mean by hurt.
The meds are safe for the chickens if given in the recommended dosage and methods with the exception of Ivermectin to sensitive individuals...don't know if anyone has the data for that with chickens.
The harm of overworming is developing worms that build up resistance to overused meds...so most recommend rotating your wormers.
Many, myself included, have chosen to keep worm load and chemical use down with herbals and good litter management and only worm periodically. I differ with the natural crowd as I choose to use meds without signs as a matter of course as I believe in being proactive since I also believe that worms are present if you have limited field (small backyard).
I don't rotate as I have chosen to remain within FDA rules for layers used for human consumption...and currently there is only 1 choice. But I avoid the harm of possibly getting sued for using nonsanctioned wormers with layers which I sell eggs from.
Lady of McCamley
The meds are safe for the chickens if given in the recommended dosage and methods with the exception of Ivermectin to sensitive individuals...don't know if anyone has the data for that with chickens.
The harm of overworming is developing worms that build up resistance to overused meds...so most recommend rotating your wormers.
Many, myself included, have chosen to keep worm load and chemical use down with herbals and good litter management and only worm periodically. I differ with the natural crowd as I choose to use meds without signs as a matter of course as I believe in being proactive since I also believe that worms are present if you have limited field (small backyard).
I don't rotate as I have chosen to remain within FDA rules for layers used for human consumption...and currently there is only 1 choice. But I avoid the harm of possibly getting sued for using nonsanctioned wormers with layers which I sell eggs from.
Lady of McCamley