Through a cut or an injury where any skin has been broken.
An infection through an animal's bite or sting.(Like the West Nile Virus which spreads though mosquito bite, or Rabies though an infected mammal's bite).
Can be inhaled or consumed and go from the lungs into the other organs causing harm internally.
The heart, lungs, blood vessels, and blood
Answer:
They digest without the use of teeth.
Explanation:
The food trickles from the crop into the bird's stomach (proventriculus or gizzard) where digestive enzymes are added to the mix and physical grinding of the food occurs. The gizzard is why chickens do not need teeth.