I’ll be carving up chickens later today and making chicken stock, homemade is best! Re:skins- onion skins are usually added to give colour, but not necessary in a beef stock. If you want a deeper caramel colour to your chicken stock, you can sear one or two, and the inner layer of skin can be left on. Outer layer skin and ends, should not go in, they add bitterness that can overwhelm the nice flavour.