I recognize that most idioms and sayings originate generations and/or hundreds of years ago. I also recognize that things were very different back in those days. Based on many idioms, I've come to the conclusion that one of the big differences between now and then is that back then much of people's time was probably spent either killing or thinking about killing animals.
Fortunately these days we think less frequently about harming animals. At least I personally am not obsessed with such thoughts, and yet in every day conversation even the nicest of us might use such phrases as ". . . like a chicken with its head cut off", or talk about "killing two birds with one stone" (bonus!).
When I was young my parents had a little thing they would say whenever they took off one of our shirts. It wasn't until I was a parent and found myself saying it naturally while getting my kids ready for bed that I realized what it even means. Then I realized that saying "Skin the kitty!" while pulling off a shirt is just awful. Like, extremely, terribly bad awful (and my parents aren't that old).
Now, I'm not the biggest animal lover. Baby animals are cute, but full grown ones I'm not the biggest lover of. Love I what is words up mixing. (whatever, Lisa) But even I am strongly opposed to these sayings when I think about it. When I don't think about it, I'm not really opposed to them at all, though.
One time when I was thinking about it, I came up with an alternate to killing two birds with one stone. It's not very clever or anything, but much nicer. I vote we ban all those terrible old idioms and come up with nicer, newer, shinier ones. At least right now that's my vote. Because I'm thinking about it.