Absolutely. Papayas help reduce digestional worms. There are so many good uses of papaya seeds that I'd save them for myself rather than feed the chickens. Treatment for: Bee stings, jellyfish stings, scorpion stings, mosquitos, digestive disorders, rheumatoid arthritis among other (less documented) applications.
Absolutely, feeding a chicken papaya seeds will not harm it in any way. Their body is actually built for the decomposition of seeds and seeings as fruits store food in the seed, it contains energy.