Very interesting Giovanni. I really like the "opposing" pairs looking at each other. You controlled the whites very well, although lighting was a bit harsh. I like the crop and composition.
I really like the action captured here. I'm surprised I haven't seen more photos like this! Thanks for sharing it :)
The crop seems a little tight on the top but that's a little picky. Harsh light and shadows aren't very pleasing but you did the best you could in the situation. A nice array of complimentary head angles.
I'd be interested in seeing a similar photo with only the heads and part of the necks showing!