I might have misspoke by putting poison as the main idea of this post, by poison I meant some kind of tranquilizer or an actual poison. Primarily a poison made from like a home cleaner, or some type of medication. Also I agree with Pancake, that the player could not eat the wolf although if you play on anything Stalker and above you probably aren't eating wolves very much to begin with as they can give you intestinal parasites. If I'm going to throw away a source of food (Rabbit) I want it to have as much value to me as it would if it were food. I'm trading a piece of my food for a dead wolf that I probably wouldn't eat in the first place. This saves a rifle round for a deer or other animal that I can actually eat.
I disagree that it would make the game much easier as poisons don't have to be extremely common and the devs have done a good job of keeping everything in balance. I've survived for 70 days on Stalker, and I now modify Stalker because I feel as though the wolf spawns are frustrating to deal with when you only have 4 bullets in a rifle, and no revolver spawns.