A 22lr is not a very humane round for body shots to any animal. Body shots with a 22lr will very possibly cause a lot of pain for the animal. With a 22 the head shot IMO is the only way to go.
I saw a guy shoot a coon dog in its side and the dog was immediately in pain. I told him to do a head shot to put the dog out of its misery. IMO there is no excuse for a body shot as first shot. Head shot first them shot to the heart. The animal shouldn't feel the second shot this way.

I have euthanized a few things before vets started doing it. 22 LR. Head.

Friends or relatives would often do the job for each other as many were deeply loved by the owner.

On the shotgun for squirrel, rabbit gun bird or Turkey. I have taken many of each using 410, 20, 16, 12 and light loads in a 10 gauge.

I quickly learned as a kid to shoot at a spot in front of their nose while in a tree or running. This put half the shot in the head and neck area and did not ruin the animal for eating. Part of my learning process was Dad's "coaching" and dislike of my skill.

For Turkeys I hold just over their head to cover the head and neck area. A body shot by a shotgun is a lost Tom.

The "recommended" way to euthanize a dog is by firing into the back of the head, toward the snout. Instant death and you don't need to look them in the eye.

Yes, but do not hit the curve at the top of the skull. The bullet will deflect and you have to put in a quick 2nd shot so they do not suffer.

I never, never poo poo the .22! I knew of one guy some years ago who fired six shots in a crowd from a cheap .22 revolver in about 1.5 seconds. He hit 4 people, knocking 3 of them FLAT on the spot. The 4th was hit just near the armpit on his left side with the bullet ending up in a lung near his heart. He very nearly died and would have but for a very quick trip to the hospital and some excellent work by a good surgeon. Shooter's name was John Hinckley.

In my opinion, Yes!

Just read this. The Washington Mall shooter of a couple of days ago killed 5 with a .22 rifle he stole from his stepfather. Rifle type/brand unstated. Not exactly a BB gun.
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Update - saw that the rifle was a Ruger 10/22.

I remember a childhood friend that had a dad that worked at a slaughter house. They always dispatched the cow with a 22 rifle. A shot between the eyes and it was down for the count.

I have hunted far more small game animals in my life than anything else, and I can say that I have probably killed hundreds of squirrels, dozens of grouse and more than a few other animals of various sizes and most were shot with a .22 and mostly with standard velocity ammo because of the noise and I used to buy it by the brick because it was cheaper and easier to get because while it worked great in my single shot Remington most semi auto firearms won't cycle it.
I try for head shots but that is not always the case but a head shot well placed is lights out. I have hit many animals in the vitals only to have to occasionally shoot them again but not always. Last year I spotted a large woodchuck on my property and in that case I used a CCI Mini Mag .22 and got him in the head at about 40 yards, he rolled over and was dead in seconds. Squirrels, well, if the shot is clear, I will hit them in the vitals, most fall right over, I would say 90% when it's a good hit and again that's with standard velocity ammo.
One animal that I was really surprised that I did so well on was a cottontail rabbit I shot a couple years back at about 40 yards. I hit him in the right side behind the shoulder, again, standard velocity .22 LR. He rolled over dead and went no where. What was really surprising was the exit hole, again this was not a high velocity round, it made a large hole in his left side as the bullet exited, you would have thought he was hit with a .22 Magnum or maybe even a .17 HMR because the bullet hit no bones on the way through.
Your best bet is to aim for the head if you want a hit that is going to be fatal almost always. Woodchucks can be tough sometimes and can take a couple .22's to the body but a well placed head shot will put their lights out. For them though and animals that size, I would use good .22 hunting ammo like a CCI Mini Mag or something that has similar performance.

The last woodchuck, got it with my old Remington 33 single shot and a CCI Mini Mag to the head. Never took a step.



This was the rabbit I got with the same rifle using standard velocity ammo.



This is the same rabbit and this is the exit hole. Again, this was just a .22 LR standard velocity round, nothing going that fast. The rabbit was dead instantly, but this was more or less a fluke. If you want your animal to have an instant lights out, put the round in the head if you can. I never had one of those crawl away yet.

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Vaya con Dios

Bobby Kennedy was killed with a .22

Probably not the answer you're looking for but, at my hunting camp we keep 3 live traps for hogs baited during deer season. Usual catch is a sow with up to 5 piglets trapped at a time. We always use a .22 with high velocity hp's to dispatch. Between the eyes 1" high from a 45 degree angle. Bang, flop every time.

FWIW, I just read an account of a point blank shooting with a .357 magnum to,the back of a guy's head. It mushroomed and he is still alive, because it just gave him a headache. I don't think anything is 100%.

Having shot many rounds of 357 mag, I have a lot of trouble believing this.

I did, too, but it was presented as the truth. Of course, just because it said .357 magnum on the barrel doesn't mean it was loaded with .357 magnum ammo, either.