1. Incubation Steve Case NSF North Mississippi GK-8 University of Mississippi December 2006

2. NSF North Mississippi GK8 What do all these animals have in common?

3. NSF North Mississippi GK8 Which comes first, the baby chicken or the egg?

4. NSF North Mississippi GK8 The egg comes BEFORE the baby chicken. The baby chicken comes AFTER the egg.

5. NSF North Mississippi GK8 BEFORE the egg hatches, we call whats inside the embryo. AFTER the egg hatches, we have a baby chicken.

6. NSF North Mississippi GK8 It takes 21 days for the embryo to develop into a baby chicken. We call this process of development incubation.

7. NSF North Mississippi GK8 3 days AFTER incubation starts. 19 days BEFORE the egg hatches. The vertebrae (back bone), nervous system, head, and eye have all begun to form. The heart has formed and begun to beat. The legs and wings begin to form.

8. NSF North Mississippi GK8 5 days AFTER incubation starts. 16 days BEFORE the egg hatches. Bones in the legs begin to develop. It is possible to determine the sex of the chicken.

9. NSF North Mississippi GK8 6 days AFTER incubation starts. 15 days BEFORE the egg hatches. By today the wing is bent at elbow. Today the beak begins developing.

10. NSF North Mississippi GK8 10 days AFTER incubation starts. 11 days BEFORE the egg hatches. By now feathers have begun to form and toes have developed. On the face, the nostrils are a narrow slit and lids are developing over eyes.

11. NSF North Mississippi GK8 12 days AFTER incubation starts. 9 days BEFORE the egg hatches. Claws begin to form; claws and beak begin to harden. Lids continue to develop over eyes.

12. NSF North Mississippi GK8 18 days AFTER incubation starts. 3 days BEFORE the egg hatches. By now the embryo has gotten into a position suitable for hatching and the beak is turned toward the air sack. The chicken embryo occupies almost all of the space within the egg, and the egg yolk begins to be drawn inside the chickens stomach.

13. NSF North Mississippi GK8 21 days AFTER incubation starts. The baby chick uses its egg tooth to break its way out of the egg. The chicks are exhausted by the time they emerge and must rest and dry out.

14. NSF North Mississippi GK8 1 day AFTER the egg hatches. The baby chicken has dried off and is strong enough to stand on its own. The chickens must still be kept in a brooder to keep warm and supplied with food and water.

15. NSF North Mississippi GK8 Image Sources http://lancaster.unl.edu/4h/Embryology/Hatc hPic.htm http://www.littleamericaminis.com/seramas/s eramas.htm http://www.rit.edu/~nlwsbi/STAGES.HTM http://www.microscopy- uk.org.uk/mag/artnov04macro/mlchicken.html