Rotate wormers to prevent resistance building up.
The only approved wormer for poultry is Wazine, and is not approved for egglayers.
There are NO wormers approved for egglayers.
A number of folks (although it would always be recommended to ask a veterinarian) use wormers off-label and toss eggs for at least a couple of weeks.
Wazine only kills large roundworms.
Here is a nice chart: All wormers should be repeated to stop the worm life cycle.