Any idea what this could be and from?

[DC1.]

A turkeys breast has very little if any contact with a hen when breeding and when he hits the right spot he is not there long enough to make a scab for sure. You are probably seeing where he sits down on the limb at night.   JS 

[WildSpur]

OK.  This area was 3"x5" by 1" deep.  He tossed the bird.  I don't think it was its bag that opened.  It was a head shot and was like this when they retrieved it.

[doublebarrel]

Again I say he took a spur and it got infected

[g8rvet]

That "bag" is the crop. Not much digestion goes on there, it is just a holding place to be passed into the gizzard for grinding.  It will have enteric bacteria in it and perforation of it will contaminate the meat around it-same for the wound.  Birds have higher body temps than mammals in general, so bacteria behave differently.  That green area on the meat is bacterial staining.  While it is not wholesome, if properly cooked, it would be safe to eat (but would probably taste terrible).  In a poultry processing facility, all that would have to be cut away to pass inspection.  The rest of the meat would be fine if you cut all that out. But if it grosses you out, chuck it.  I had one I killed one time that had been shot with a rifle ball through the breast. It stunk and was stained green. I cut out the healthy breast (just one side) and tossed the rest. It tasted fine.