I thought I did research on a reliable source and found Levamisole as a good deworner. But after more research I found this was not allowed either for chickens. I changed my post. It seems only Flubenol is allowed.Levamisole is a very good wormer, I use it.
Rotating areas where birds forage is best as well as keeping grass cut short. Birds kept in pens or on the same soil are susceptible to frequent worm infections. Sand in the pens helps as well as scooping poop helps deter worm infections.
Waiting time is only 1 day for slaughter cattle, and no waiting time for eggs.