Stir 1/2 cup melted butter with onion, celery, green pepper, mushrooms, garlic, and herbs. Season hens inside and out with salt and pepper. Stuff bird with equal amounts of the vegetable mix. Place birds in baking dish, breast side up. Drizzle with remaining 1/4 cup butter. Cover and bake 1-1/2 hours at 325 degrees. Brown at 500 degrees.