A killing cone is a cone-shaped piece of material in which you place your chickens to be dispatched. It can be bought or constructed, made from metal, plastic or rubber. Their heads stick out of the bottom & their feet & tail stick out of the top. You hang it up, place the chicken in there, and either slit their throats or cut their heads off. The cone holds them in place while they bleed out and keeps them from reflexively flapping & running around after they're dead. You could instead use rope or zip-ties to hold their legs together & hang them, and duct tape to secure their wings to their sides.