Originally Posted by crazy banana

Vermicides will kill intestinal worms in horses and other livestock, but once excreted, they will break down quickly. Especially when the manure is hot composted, it will not harm any earthworms or other nematodes in the garden if applied.
I have read that currently the FDA is doing some studies on livestock vermicides. However, it will probably take up to two years until they will be able to publish the results. Until then, certified organic farmers are allowed to use manure from non-organic livestock on their crops and still call their produce organic.
Anybody who has ever used any horse manure in their garden will confirm that one of the best ways to increase the amount of earth worms in the yard is to put out a load of manure.

And BTW, Kat and other poultry lovers as this is a thread in Tiki Hut: chickens DO need to be de-wormed, too. Just because someone does not see any worms does not mean that they are not existing. However, I totally agree to do a fecal egg count sample.