In April I will be picking up my first chicks, 15 Welsummers. I will be using Purina Start & Grow (only other choice is DuMore). I will be starting them in the basement, and moving them to the chicken house and tractor when they grow enough. I don't want to end up with left over starter feed. How much feed can I expect them to use? Any Idea how much Layena 15 grown chickens use if they can be out in a chicken tractor? Probably seems simple unless you never did it. Thanks.