A very graphic image Sanjeev and it tells a real story. As far as the crop goes I would consider cropping off the left to reduce the amount of space upper left. This would crop the leg some but I tried it and for me is seemed to work. I think this crop would balance the image better.
I'm on an iPhone today, traveling, and can only see a small image. It looks very interesting -- the story of life and death in Africa. It seems good technically from what I can see here -- I'll leave it to others to comment on that aspect. I could wish the camera had been a little more to the left, but I realize that may not have been possible. From this position, if the camera had been pointed just a little to the right it would be better, and John's suggested crop would help do the same thing.
It looks like you found some good subjects on this trip. I hope to see more!
Seeing it on a bigger screen now, I'm surprised at the limited DOF at f/8. Going to a higher ISO would have allowed a smaller aperture, bringing the wildebeest's head more into focus -- maybe f/11 or even 14 would have been better. A full-frame camera inherently has less DOF than a crop sensor for the same composition of a scene at the same aperture. ISOs up to about 1600 are generally good with the 5D3 as long as you don't need to bring up underexposure.
Having a meaningful foreground element OOF is often not the best thing. When grass goes OOF in the FG that can be good to simplify the image, but here, I think many people would want the head a little sharper, as his plight is also a major part of the story. Or else make the DOF even shallower, so the focus is more intentionally on the vulture.