What is a physycle?

Do birds break down food by chewing it with their teeth?

it is un-certain that birds do chew, their food, but mammals do. But, the next best thing to a vegetarian bird that chew it's food, are the ornithops, a group of plant-eating dinosaurs which includs ceratopsids (triceratops) and the hadrosaurs (duck-billed dinosaurs) sadly like all the other dinosaurs they went extinct 65 million years ago, but it might be possible (atleast possible) if not likely that modern plant-eating birds may chew their food with annomal ridges the the sides of their beacks as they move them up and down while the ridges them selves cut up the vegetation into smaller bits, only to leave the rest grinded up by stones in their stomachs, so that the digestive juices could get back to work. So, like with mammal hervibores, as the bird's stomachs digest, the bird itsealf (the body) will be back in physycle order to their daily eating.