Sorry, but I never knew about the no last meal rule in the 80's. I just did what my grandmother did, went and got the one I wanted for dinner or the freezer the day he was needed. No problem, just be careful where you cut, do not cut into the gut. Here is a photo of the "chicken Killer knife" -- my children to this day will not touch this knife, they are over 30! I got it from my brother-in-law who worked in a processing plant in Kansas. He retired with carpal tunnel he butchered so many chickens with knives like this. I got this from him because it was sharpened so many times it no longer met specs for the company he worked for, so he gave it to me. My birds did not know what was going to happen, until I hung them up in the garage.
Yeah, the no last meal thing may be overkill (no pun intended). It does cut down on the amount of poop in their digestive tract, which tends to ooze out and get all over everything during their death throes if I haven't withheld food overnight. But it's not essential. It's just how I do it.
I try not to let them know what's happening either, until they're getting hung upside down in the tree. I do keep them in a holding pen overnight because they find that less suspicious and scary than me chasing them around the coop/run in the morning.
That knife is awesome. Similar shape to the one I use, but yours looks like a much better knife.