Grit size

[ChickenCanoe]

Grit that is too small for the size of the bird is pretty worthless. It will just pass right through the gizzard along with undigested food.
These sizes are similar to those I've seen on other charts.
What size poultry grit do I need?
Cherry Stone Poultry Grit comes in four pre-sorted size options:
Poultry Grit #1 is the smallest with average size of 1/16”. It is best for turkeys age 1-5 days or chickens age 1-3 weeks
Poultry Grit #2 averages 3/16”. Recommended for turkeys age 6-21 days and chickens age 4-6 weeks
Poultry Grit #3 averages 5/16”. Recommended for turkeys age 3-8 weeks and chickens age 7+ weeks
Poultry Grit #4 averages 3/8”. Recommended for turkeys age 8+ weeks
When deciding between sizes for your birds, it is usually better to select a larger size than smaller.
(From TCC Materials)

 

[The Farmers' Daughter]

Grit that is too small for the size of the bird is pretty worthless. It will just pass right through the gizzard along with undigested food.
These sizes are similar to those I've seen on other charts.
What size poultry grit do I need?
Cherry Stone Poultry Grit comes in four pre-sorted size options:
Poultry Grit #1 is the smallest with average size of 1/16”. It is best for turkeys age 1-5 days or chickens age 1-3 weeks
Poultry Grit #2 averages 3/16”. Recommended for turkeys age 6-21 days and chickens age 4-6 weeks
Poultry Grit #3 averages 5/16”. Recommended for turkeys age 3-8 weeks and chickens age 7+ weeks
Poultry Grit #4 averages 3/8”. Recommended for turkeys age 8+ weeks
When deciding between sizes for your birds, it is usually better to select a larger size than smaller.
(From TCC Materials)

That's helpful. I've been using #2 for my flock. Next time I think I'll get #3.

 

[ChickenCanoe]

There is a similar chart at the bottom of the following page.

https://www.scratchandpeck.com/grit-because-chickens-dont-have-teeth/