I've heard lots of pros & cons about this. Right now there are many birds in the laying flock molting, and they're not producing many eggs. There was a bad infestation of roundworms early this summer & I gave them both Wazine & Ivermectin pour-on then. I've taken their water away tonight & am seriously considering giving them another dose of Wazine tomorrow. And if Ol' Murphy is listening, he'll make them start laying more while I'm waiting for the withdrawal period to end!
As you said, you've heard the pros and cons. It is obviously a personal decision. In my personal opinion, if the flock is otherwise healthy, I'd do it for sure if I had reason to think they had worms. It probably takes more energy and nutrients to lay eggs than to grow feathers. Worms sap energy and make them unthrifty. I would rather worm them when they are molting and not laying instead of when they are laying and not molting. That is just my personal thought and I know I have weird thoughts and convoluted logic. Above all, I am no expert on this subject. Good luck whichever way you decided.
With the wormer Safeguard/Panacur/Fenbendazole, if you worm while molting, it can cause feather deformities. Not sure about other wormers. From http://www.exoticpetvet.net/dvms/skin.html It may be important to note that administration of fenbendazole, metronidazole or other drugs may affect developing feathers and cause temporary feather abnormalities (which will resolve upon the next molt.)
Good information. I mistakenly thought it was a thriftiness thing. Since I don't show chickens or breed to standards, I still would worm during a molt if I saw evidence of a worm infection, but it certainly gives you something else to consider. Thanks.
Well, I've gone ahead & done it, gave the laying flocks Wazine in their drinking water on Sunday. I've not done this before, worm them just because or while they're molting. But they had a severe infestation of roundworms early in the summer and our climate makes for a big petri dish in the yard. I haven't seen any more evidence of roundworms, nor was there any shed where I could see them after they drank the Wazine water. But I wanted to prevent any future outbreaks. I figured now was a good time to worm since they aren't laying many eggs anyway, so there would be less to discard during the withdrawal period. My hens have to sell most of their eggs to help pay for their feed, and they don't want to lose customers. Now here's another question: Do you feed the eggs they lay during the withdrawal period back to your layers? Again, I've heard conflicting arguments. Some say No Way, you're just prolonging the withdrawal period by feeding them eggs tainted with the medication. Others say Why Not, the amount of medicine in those eggs is really minimal, it won't affect the next eggs to come. I've been giving them back their eggs, figuring the extra protein & calcium will help them as they recover from their molt. I put them in the blender shells & all and cook them scrambled. Today I put a few cloves of garlic in the blender with the eggs for extra goodness. I'm feeding 6 eggs to 60 hens so I think any residual medication they get back will be minimal. But I'm open to hear other points of view...