If anything, its gotten harder to kill the chickens we are going to eat. It was always hard, but after 18 months of doing it, its even harder.
Maybe its because we are currently killing a couple of young Buff Catalana roos a week, and they are SUCH sweet chickens. They act wild, and they are subject to quick panics, but if you catch one, they settle right down in your arms. THey don't scream or try to peck you or anything that the others will do, even fairly tame ones. Its weird, because the Buffs didn't get much handling as babies, either. For the first time, we kept the brooder box up in the coop instead of on the front porch, so they didn't get picked up and petted a dozen times a day. They just seem to be nice, nice chickens.
Its almost easier to kill the ones that flap and scream and carry on, because you want to get it over with.
Either way, I don't think you should eat meat unless you are willing to kill it yourself. DH and I do it together. I hold and pet them and he quickly snips off their head with pruning shears. Quick and clean.