Our 2 week old Pekin duckling was pecked so bad on the back of the neck that we can see muscle need

[nanastella]

Our Rhode Island Red hatched the duck egg and was taking care of the duckling like it was hers and all of a sudden we went out to the barn tonight and the 2 Rhode Island Reds were in the barn and my husband found my duckling with her neck with an open abrasion 1in x 1in and you can see the muscle. No clue what happened. We put neosporin on it and we brought it inside the house and will keep it seperate. It is drinking water and eating. We are not sure what else to do, we could use some advice. Does it need stitches? Should I take it to the vet? Never experienced this. Thanks