Supplement with grain; the starter/grower should remain the main portion of their diet. No bird is too young to be wormed if there is an indication that there is a worm problem; however you need to be careful with dosing youngsters, If they are September hatchlings, that makes them 3-4 months old. I would use ivermectin pour-on in their wing-pit or give them piperazine.
There are shows all year long--but in different parts of the country they tend to be at different times. Here in the southwest show season is slowing down-pretty much starts in October and ends in February. Likewise, birds molt at different times depending on where you live. However, I am used to fall molting, I don't recall ever seeing much spring molting--by then they are re-growing their feathers and going broody (hens often, but not always molt after raising a clutch).