how old should chicks be when they start getting grit?

Start giving grit when you start giving treats that they need it for. They make chick grit and I don't think there is a certain age that they can magically have grit or need grit.

 

I was giving free choice chick grit to my day old chicks. If they wanted it, it was there. If not, my two week old chicks were there to eat it, too.

 

It depends on what they are eating. They don't need it if they are just eating chick starter or the equivalent, but as soon as they have access to grass, etc. they will need it. Offering it can't hurt anything.

 

Our entire farm is grit!!!

In other words, I feed only chick starter with the occasional egg. So, they'll get all the grit naturally when they hit the dirt at 6-8 weeks.