Be prepared for the death throes - where the muscles release and contract and release just prior to full bleed-out.
I CAN slice the veins, but I choose to let my man be my man and take this part of the job.
We say a prayer of thanksgiving for each bird prior to putting in cone (like while we're walking bird from run to processing area).
Have processing area AWAY from view of other chickens. They know what's going on - really, I swear they do. But they seem to 'forget' quickly. (like a week or so). If you are the one to catch the chickens; once processing is complete, take out the living some super-special treat (oatmeal with raisins; mealworms; hot sweet potato cut into chunks, etc.). That helps them to realize you provide great things. Keep it up for a few days afterwards too.
Be prepared for the heat of the body and the unique smell of chicken innards. Can't describe it any other way. Processing in the cold means that the carcass steams (seriously!). That was new to me - guess I didn't notice it when processing in July!
Yes, it's hard on the tenderhearted - but all things are created to provide for others. Chickens provide lots of good things, the last being, meat for your table to sustain your family. God is good.
Rigor will pass in 2-4 days in fridge, so make sure you've got some room to put 'em all in the fridge! And some 1gal or even 2gal size Ziplock bags so the meat doesn't dry out. My sons are now pretty calm about seeing a chicken on the top shelf of the fridge - first time though, they were a bit surprised (son asked "Is that Roaster or Napoleon?" My response, "that's Roaster, that's Napoleon", son, "oh, ok, I just was wondering where he went!")
Best wishes! Once you taste the product of your own hands, it's hard to go back to blah grocery store! Doesn't matter if it's tomatoes or squash or green beans or cow or pig or chicken. Yummy stuff!