We have some old hens we want to process and we have a meat grinder so we thought about trying it since the meat is usually more tough on them. After we butcher, do we cut the meat off the carcass right away and put it through the grinder? Do we put the carcass in the fridge and wait the 3 days and then cut it off and grind? Do we grind raw or should we cook it first? Add some skin? No skin? If someone could give me some direction or send me to a link that would be great!