My plan was to use a commercial wormer every 6 months but to give fermented feed mixed with a heavy dose of cayenne pepper every week. For the commercial wormer I switched to ivermectin pour-on (off label...designed for cattle) because it was supposed to work for external parasites as well. I had a bird die but it wasn't fresh enough to send off for necropsy. Then I had another die which I did send off. Before I got the results back I lost another bird. When I got the results back my bird had died from capillary worms. It's one of the few parasites NOT controlled by ivermectin! So...I used Safegard (the best thing for capillary worms) and now I give all my birds a dose of Safegard every month. My birds are all confined so I can't get by with worming every 6 months. Now, all this time I had been giving fairly massive doses of cayenne (I get it cheap in bulk). It might have helped with some worms but it certainly didn't keep my birds completely clean of worms. In fact that necropsy also found ceacal worms and one other type but in negligible numbers (perhaps held in check by the cayenne but I also used the ivermectin). It sounds great to use all natural solutions and if you free range you might be able to get away with it but a commercial wormer really does work.
There is no evidence to say that ivermectin is an effective wormer, in fact the papers I've read state that the amount required to make it useful as an anthelmetic in poultry would be enough to kill the bird. Ivermectin has been overused worldwide and is loosing its effectiveness even in the livestock that it is labelled for. Lots of people use it to control external parasites but I wouldn't rely on it for internal parasites.