Yes a pigeon doesn't have much of a neck so the head doesn't seem to move much in relation to the body. They also tend to sit quite still. I've watched videos of guys hunting them and chest hits put the lights out very fast. However, for something like a squirrel or similar, they seem to move the head a lot so I question the idea of a head shot as it's a small target. Using a high velocity 177 wouldn't a shoulder hit be easier to make, especially in the field?
Think of it this way, when you shoot big game you hope that your target drops where it stands, sometimes this happens but in a lot of cases it doesn't with a boiler room shot.
You end up having to track the animal for a bit, even if it drops fairly close.
Similarly a body shot to a squirrel may not put it down immediately,allowing it to basically disappear,in a hole,or a tree,or just in the bush.
A head shot usually drops them right away.
A poor head shot usually is a miss, or a hit in the neck(usually fatal), a poor body shot can mean lingering death.
Another thing to consider is that there is very little energy transfer(shock) using a pellet, My HW 97kt in .177 almost universally gives complete pass through's on game up to rabbit size.
Pellets don't usually "bowl them over" unless you are using a big bore PCP.




















































