Do you have a wildlife rehabilitator or a swan goose sanctuary in your area? In the UK there is community education so the public will feel empowered to help, heal and release injured wildlife, but in North America we keep the public ignorant and frighten them with rules and regulations so nobody thinks they can do the right thing. You did the right thing in helping and you know it inside. Feed whole corn and lettuce, and a bit of bread for a treat. It might like your chicken scratch too. Keep it safe and enclosed because it will be vulnerable to predators if it tries to escape in that condition.Maybe you know an avian vet who could check the wing?