If your gonna wanna kill one, here’s a tip: Bring a lightning wyvern as they deal LOTS of Damage with its lightning attack, or a good Rex, even a pack of good DireWolves.
Now, IF it’s an ALPHA, here where I gets complicated, I recommend bringing a rockgolem with at least 40.K+ Health, and high melee as alphas have resistance, a good lightning wyvern (Again) And at least 3 Good Rex’s with 50.K+ Health, and it would have been a dead giant sausage..
Get a dino with around 1000 hp and 1k melee and you should defeat these easily. I find fire wyverns are best but you can also use thylas, rexes and alot of other stuff. Sometimes you can spot them as they spawn in so keep an eye out while going across the desert and you should find some pretty fast. Got 15 horns after 30 minutes on my fire wyvern (2000 hp and around 1.4k melee)