We have lilies (scads of them!) in our chicken run. Lilies are toxic to chickens. But in the several years the lilies have been there, we have yet to lose a chicken, or to have a chicken sickened by the lilies. They scratch under and around them (bugs!); they shelter under them for shade. But they do not eat them or even nibble on them. I think you'll find the same with gourds. If they are toxic to chickens, the birds will leave them alone. If they are not toxic, they will devour them!