questions on egg shells and chicks

[chicks are me]

I have heard that you can bake egg shells and let your chickens eat them for calcium, how can you do that and is it safe for the chickens? the egg shells can be very sharp.
I also am wondering about chick grit,i am getting my chickens earlier this year (april 15), so i don't think i will let them out as often, unless it reaches 80+ degrees, so should i get chick grit? If so what brand to you recommend?

 

[Feathers n Fur]

I often bake the shells and let the girls eat them. I rinse them and let them collect in a container til I have enough to cover a cookie sheet then after I cook dinner I just plop them in the turned off oven for about 10-15 mins or until I remember I put them in there. Some edges turn a bit brown. Once cooled I put them in a plastic baggie and crush them. The smash up nicely into tiny pieces since they are brittle from baking. Chickens enjoy them. I use them alone in place of oyster shell or I will sometimes mix them in.

As far as the grit goes..I buy whatever chick grit TSC has on hand. and never had a problem.

 

[chicks are me]

Thanks!