Some wormers do not have a discard or "withdrawal" period because the medication is not transmitted in significant quantities through the egg, because their ingredients are natural and non-chemical, while others (usually prescribed by a veterinarian, do require that you toss any eggs laid during treatment.
You will want to consult a vet before treating your chickens for worms with any sort of medication. Your vet can perform a fecal smear to determine if your chickens have worms and what type they have, in order to provide a good recommendation for treatment. If you treat for round worms when your chickens have another type, your treatment won't do any good!
Another word for "wormer" you may see used is "anthelmintic." Wormers are often called "de-wormers," too!