I wormed them once cycle, two doses 10 days apart, had to discard about a month's eggs from my layer operation which worked out to 117 dozen worth $467. Cheaper to let the birds have worms, for sure, as I could have sold for soup and replaced 2/3 of my flock for that amount. After treatment I did not find visible worms in the droppings nor did the condition of the birds change.
What made you worm them in the first place?