So I got 50 cornish cross chicks from Welp out in Iowa. They've been with me now for 9 days... yesterday, our 4 month old puppies started pooping roundworms. Ahhhhhh! Took them to the vet, they've got their medicine, and looks like they're fine.... They do ocasionally visit our brooding pin however. Puting their paws up around the side and looking down into them (they're are GSPs... Mmmm birds). I've never given anything to these chickens for meds. Straight 20% feed from our elevator, and water. Do I need to do anything? The exhibit no signs of ill health, and I have yet to see any worms from their direction. They are in a confined area.
Most worms are species specific or at least birds usually get different parasites than mammals. Odd are your cornishX are fine.