Windows on Life
This is a protocol for windowing live fertilized chicken eggs to allow
to observe living development in action. Students open the egg at
72 hours after incubation has begun. They can open the eggs and make
for several days using this technique. This protocol was developed in
conjunction with research
done at Idaho State University in Dr. Trent Stephens lab.
Fertile chicken eggs - local supplier (check the organic grocery)
Chicken Ringer's Solution with antibiotics (avl. from synoptic
houses for less than $20.00 a liter)
Fine-tipped forceps and dissecting scissors
Sterile alcohol swabs
Sterile 10 cc. syringes with 18 gauge needles
Cardboard egg cartons or trays
Allow a full 45-50 minute block of time for the first day and 15 minutes
day of observation.
- Eggs need to be incubated 72 hours to allow embryo to develop to
enough for students
to see the heart chambers and pumping action. Eggs may be kept at room
for several days prior to incubating. Start timing when they are placed
in the incubator. This allows you to plan the day you want to start.
Do not turn eggs.
You want the embryo at the top of the egg.
- Have all scissors and forceps soaking in alcohol. Be sure that
they are air-dried
prior to using on the egg because the alcohol will kill the embryo if
- Swab the narrow end of the egg with an alcohol wipe and remove
5cc of albumin by
carefully inserting the 18 gauge needle on the syringe into the narrow
end of the
egg with the needle tipped at a sharp angle to avoid the yolk. This is
to drop the
embryo away from the surface
you will open.
- Swab the top of the egg. Secure it in a nest of paper towels in
a dish or bowl
of some kind to keep it from rolling. Gently open the top of the egg
with the tip
of the forceps or tip of the scissors. Then remove enough egg shell to
have an opening 1.5cm X 2.0cm. The eggshell may be ragged but be sure
the membrane inside the shell
does not fall down and touch the embryo. This tends to "wick dry" the
- Drip 5-6 drops of room temperature Ringer's solution with
antibiotics onto the surface
of the yolk not directly on the embryo. Do this with a sterile syringe
with no needle
attached. Observe the embryo. This is best done with a stereoscope.
Don't allow more than 15 minutes observation time. Have students draw
the embryo and attempt
to label the landmarks. At 72 hours you will have a heart with
chambers, limb primordia,
somites, head, optic cup and nerve cord.
- After observing. Have students cover the opening with transparent
tape. It is
sterile on the roll and if they do not touch it on the adhesive side,
as a sterile patch. Be sure they run a fingernail over the tape on the
seal the egg completely. If their hole is too wide use two pieces of
tape and use a fingernail
to be sure that the two pieces adhere to each other.
- Successive days the tape may be opened with sterile scissors and a
new layer of
tape applied over the old tape after observations. DO NOT ATTEMPT TO
FROM EGG SHELL!! Additional Ringer's solution should be dripped in
daily as soon
as the egg is opened. Again limit your observation time to 15
I have an alternative method for windowing that uses clear plastic wrap,
and petri dish lids. The survival rate is lower but the observation
time is continuous.
If you would like a copy of this protocol, please email me at
and I will be happy to send you a copy.
NOTE: A word about vertebrate use in the classroom
I know there is a controversy about the use of live vertebrates in
I have done this lab for many years with sophomores and seniors in
classes. It is always a very popular lab and I use it to generate
the use of live animals in the classroom in addition to teaching
have come back after years away from high school and still remember this