I just got 7 chickens from a friend who had a flock of over 20. They let their chickens free range all over their yard/field and also feed them but they are thin (I think). They are red sex links and white rocks. Very friendly chickens but ravenous. I feed them meal twice a day and throw out everything I have for them, scraps, weeds, old lettuce/veggies, stuff from the garden, ANYTHING I can find. What can I do to get some meat on their bones, or are these breeds supposed to be on the thin side?