Hmmm, a number of posts already on both sides of the debate and yet, and yet, no one has pointed out that the drone operator was quite possibly breaking the law while flying the drone. (would seem from the article that it was not within his range of vision at the time)
As for the appropriate load for drone, I don't think salt will get the distance unless the thing is within 50' of you. Salt doesn't carry well. I would use #2 bird, and depending on how good a shot, maybe #3 depending on how flitty it is, and distance.
As for shooting "wildly" I would disagree. The shooter apparently hit was he was aiming at, we don't have any reports of collateral damage, and no one is complaining about pellets on their car, or windows, etc. Nothing wild about this shooting.
I"m guessing in Joyzee, he's toast. In TX, I doubt there would be an arrest. If it did go to court, I can't see anyone voting to convict. Sure as hell, if I'm defending the guy, I bring a drone into court(for information and clarity of course), and hover it right over the jury box for a good 15 minutes; "Not guilty!"