The 96-hour chick embryo

chick embryo, visible embryo, embryo image, embryo research, embryo fetus, embryo cloning, chick embryo, visible embryo, embryo image, embryo research, embryo fetus, embryo cloningAt this later stage in development, there will be many obvious structures to examine (see image below). Open these eggs following steps 2-6 above. It will not be necessary to remove the embryo from the egg shell.

96 hours of incubation - The embryo appears to lie on one side on top of the yolk. Note the curvature of the body and locate the major areas of the brain. The developing eye will be prominent, as well as the beating heart. Next to the heart will be a protruding mound of tissue, the forelimb bud, which will become a wing.



More posteriorly, somites will be visible. It may also be possible to see the early hindlimb buds. Locate the yok sac (it is rich in blood vessels) and the allantois. The allantois will expand greatly during the next few days of incubation (see 5-day and 6-day images below and labeled 6-day image), making it more difficult to see the embryo. Eventually it fuses with the chorion to form the chorioallantoic membrane. This membrane is also rich in blood vessels, and has been used as an experimental model system for identifying molecules that stimulate or inhibit the growth of blood vessels. It is also a useful site for grafting bits of tissue from other embryos (even mouse embryos) because the blood vessels will grow into the grafted tissue and set up a temporary circulatory system.

chick embryo, visible embryo, embryo image, embryo research5 days (120 hours) of incubation

limbs are considerably longer
contour of digital plate is rounded groove between 2nd and 3rd digit is visible demarcation of first three toes distinct

embryo fetus, embryo cloning, chick embryo, visible embryo, embryo image, embryo research, embryo fetus, embryo cloning6 days (144 hours) of incubation

wing is bent at the elbow second digit is larger than the others grooves between the first, second, and third digits grooves between second to fourth toes beak is more prominent than in stage 28 no egg tooth visible yet.

embryo fetus, embryo cloning, chick embryo, visible embryo, embryo image, embryo research, embryo fetus, embryo cloning10 days (240 hours) of incubation

distal segments of limbs are proportionately longer nostril is a narrow slit flight feathers are conspicuous feather germs cover the tibiofibular portion of the leg lower eyelid has grown upwards to level of cornea circumference of lids is a narrowing ellipse.

chick embryo, embryo image, embryo research12 days (288 hours) of incubation

primordia of scales marked off over entire surface of leg external auditory meatus is surrounded by feather germs sternum covered with feather germs except along mid-line upper eyelid is covered with feather germs lower eyelid covers two thirds to three fourths of cornea.

visible embryo, embryo image, embryo research16 days (384) hours of incubation

beak length from anterior angle of nostril
to tip of upper bill = 4.8 mm.
third toe length = approx. 16.7 mm.

, embryo image, embryo research16 days (384) hours of incubation in shell

beak length from anterior angle of nostril
to tip of upper bill = 4.8 mm.
third toe length = approx. 16.7 mm.

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