Grit in a nut shell??

Can someone explain grit in simple terms?
I understand they need it to grind food but I am confused about the crop and gizzard etc.
Thanks

Grit is just sand and small pebbles they use to grind thier food in the gizzard

The crop is a "pocket" in the throat that stores food until it moves into the gizzard to be ground

The crop allows birds to pick up a lot of food in a hurry, then carry it back to a safe place to digest later

Grit:
There are essentially two different types of poultry grit available.
Granite or insoluble grit passes through the bird to the gizzard and is used to grind down food so that it is more easily digested. This grit has to be a suitable size for the size of the bird. Grit that is too small will simply pass straight through the bird and will not help the bird at all so it is worth checking that the grit you are buying is for the correct age of bird. Grit is usually classed as chick, grower, layer and turkey. It is better to feed a grit that is slightly too big than too small.
The second type of grit you can buy is known as soluble grit or Oyster shell grit. This is usually ground up Oyster shells but can also be Cockle shells or limestone. Oyster shell grit is larger than Granite grit and dissolves in the digestive system, providing the bird with sufficient calcium to produce strong bones and good egg shells.

Crop:
An organ, a part of the esophagus, located at the base of the neck and used as a storage place for food after eating but before digestion.

Gizzard:
The muscular stomach of the fowl where the food is ground and mixed with the digestive compounds produced by the proventriculus (glandular stomach).



Chris

i can't add anything, but just want to thank you for the diagram.

Thanks for the excellent responses. I am starting to get it.