Have you noticed any of her sibs that might be close to her size and might try those 2 together and see what happens. Don't even try new mama and ducklings or poor Biddy will be hurting again.
Here is Buddy. He or she is a lot smaller than the clutch. This is the one they had almost pecked to death. The beak seems to be healing nicely. She acts a little slower, has some shortness of breath on a lot of exertion but adapts. Her bottom mandible on her bill seems to protrude. I tried again to reintroduce them. The lead sibling pecked her immediately with another following suit. I don't think they will ever take it back in. I'm at a loss on what to do. Just keep her pinned up and wait? She is next door to another momma who has one week olds. So she isn't as lonely but I'm sure they won't take her in either. Thoughts?