I never feed treats to chicks till they're over two MONTHS old or so. You lower the protein levels too much when you do that, IMO. Dont be too anxious to supplement their starter right now with anything other than perhaps hardboiled chopped eggs, which is protein.
This is one of those things I don't get unless people just want to entertain themselves watching the chicks run around the brooder playing keep away, feeding treats to chicks. They don't need them and it does more harm than good at a very young age. That doesn't apply to tossing them a cricket or two once in awhile, more animal protein. That's just my take on it. Spaghetti squash wont hurt them, but it isn't something I'd advise at their age. They need grit if you start feeding them extra stuff, too.