Feet Cookie is missing part of a toe.

I noticed my piggies' toe nails are getting a bit sharp/long and thought it was time to trim them. Cookie is young and wiggly, so I had my boyfriend hold her while I clipped her nails. This was the first time I was able to get a good look at her feet. On one of her front feet, her 2nd toe has no nail, looks like it missing part of the knuckle, and is basically just a stump. It doesn't look like the nail got ripped out and just never grew back, like part of the toe is actually missing.

Has anyone seen this before? I guess what I'm wondering is if it's a birth defect or an old injury. However, there's only so "old" the injury could be since she's < 6 wks old.