I hope no one is offended but I have considered harvesting them to feed my family but I haven't done it before and I am afraid of wasting or not being humane.
There are some people on this forum who happily eat chickens they raised, and some who would never do it. The meat bird forum is a good place to look for the ones that approve of eating home-raised chicken.
About being humane: the only thing you have to get right is the killing. After that, no matter how much you do things "wrong," it cannot hurt the chicken.
For killing, I prefer to chop off the head with a hatchet or machete, on a chopping block. There is a way to hold the chicken upside down-- hold the feet and the wing tips--and they will usually be still and stick their neck out. Then I lay the neck on the chopping block and remove the head with one quick chop. (Of course, use a sharp blade, and I try to hit harder than I expect is needed, because I want to be sure the head comes all the way off with the first stroke.)
Some people use a killing cone to hold the bird still. I've read of folks using knives, or someone used those big cutters meant for tree branches: they put the bird in the cone, carefully lined up the cutters, and then cut quickly.
I read of someone who held a chicken down on the ground and shot it in the head with a pistol.
Lots of other methods exist too, but these are the one I have used and the others that I personally might be inclined to use, depending on circumstances.