ANATOMY

Detailed explanation-1: -Many species swallow stones and grit to aid in digestion. These stones remain in the gizzard and crush the food as the gizzard contracts. From a functional perspective, gizzard stones in birds are the equivalent of teeth in humans.

Detailed explanation-2: -To improve the efficiency of digestion, many birds ingest and retain grit in the gizzard to break down food particles, similar to the use of teeth by non-ruminant mammals (Fritz et al., 2011).

Detailed explanation-3: -Birds use a muscle in their stomach called the gizzard to grind food down into tiny particles ready for further digestion. Once food particles have been processed in the gizzard, they move through the small intestine for nutrient absorption and later the lower intestine for excretion.

Detailed explanation-4: -The gizzard can grind the food with previously swallowed grit and pass it back to the true stomach, and vice versa. In layman’s terms, the gizzard ‘chews’ the food for the bird because it does not have teeth to chew food the way humans and other mammals do.

Detailed explanation-5: -When present in the gizzard in reasonable quantities, flint-type grits have two main functions: to divide and separate food particles so that the digestive, enzyme-like secretions from the proventriculus and the mineral acid of the gizzard can permeate freely. grinding and crushing.