What are these dark areas in turkey meat? I have some amount of prepackaged sliced turkey meat that otherwise smells and tastes good.

Today though I noticed that a few slices have darker spots in them, like as shown in below photo. A vast majority of the slices in the package do not have any spots like these (perhaps most of the slices in the package do not come from the same turkey).

In case it is useful, the use-by date on this package is April 13th 2018 (about 3 weeks from today); I opened the package 4 days ago.

The question I wanted to ask:

What are these dark areas in turkey meat?
I find when carving turkey that when you carve the last slice from the breast , you get marks like that , in the same place, where the bones jut out into the meat.