Some of this, I think, is based on differing opinions and different experiences.
At 3 days old my group ate a moth that flew into the brooder. I was very concerned. Someone suggested I give them a little grit just to be safe. So I bought Parakeet grit & gravel at the store. It is very, very fine (like sand). And.. I figured if my chicks were with mum, they'd be eating all sorts of stuff at that age. I didn't really give them any treats (nothing they liked, anyway!) until after they were 1.5wks.
I think the problem with the "chicken gravel" is that the pieces are too large for tiny chicks. I've heard some suggest driveway sand, or even dirt. My fear here is that my hubby is a bit of a gearhead, and there very well could be chemicals mixed in with anything laying on our driveway!
As far as the chick crumbles go, I've heard conflicting info on here about that, too. Some say it has grit in it, some say it would say on the label. I checked my bag.. nothing listed about it at all.
So... I know that's probably not much help, but I think it may be a judgement call.. at least that's how I felt about it at first. I do go VERY light on the treats at this point (my group is almost 3 weeks), and only give them a little gravel to go with it. LOL! Actually, I haven't dare give them anything I would consider a choking hazard. I gave them cooked peas last night.. but mashed them first in my fingers! I'm so panicky...
Guess it's the mom in me!
Meghan