Are chickens the only animal that has gizzards?

Question

Are chickens the only animal that has gizzards?

Answer 1

"Emus, turkeys and chickens, like all birds, have gizzards. Mullets (Mugilidae) found in estuarine waters worldwide, and the gizzard shad, or mud shad, found in freshwater lakes and streams from New York to Mexico, have gizzards. The Gillaroo (Salmo stomachius), has a gizzard. It is a species of trout found in Lough Melvin in County Fermanagh, Northern Ireland. It is a distinct species, characterized by a rich coloration. Its gizzard is used to aid the digestion of water snails, the main item of its diet.

Crocodiles also have gizzards."

Answer 2

Have you never cooked a turkey?  The gizzard is part of the giblet package stored inside.  Birds do not have teeth- their jaws are not strong enough to support them.  Instead, they forage and store the food in their crop, then feed it into their gizzard.  Think of it as an overactive muscular stomach.  By eating grit (sand or stones), the muscle action grinds up the food for digestion.