Why would worms leave their host when they are sitting their feeding off nutrients meant for your birds? They are mating as well. They lay tens of thousands of eggs a day and the eggs are excreted in feces onto your soil. Chickens continually peck the soil, they pick the eggs up and are swallowed and are reinfected.I know very little about worming to be honest, but I dont see worms in poop so I assume I'm doing okay.
The only time you'll see a worm excreted is when it is old and dying OR there's no more room in the guts and it's excreted out the rear end. Worms cannot survive outside the host.