Before and After: The Chicken and the Egg

Before and After: The Chicken and the Egg Intended for Grade: Second Subject: Math Description: This project provides practice using concepts of the calendar and time-related vocabulary by exploring classroom incubation of chicken eggs. Objective: The students will predict when the eggs should hatch using a calendar and will be able to apply time-related vocabulary words to order the different steps in the embryo s development. Mississippi Frameworks addressed: Math Framework 3b: Using collected data from students and other resources, create line, bar, and pictorial graphs. [2007 Framework 5b] Math Framework 3c: Interpret graphical data in terms of more, less, same, most, and least. [2007 Framework 5c] Math Framework 4b: Identify vocabulary terms for time (e.g., before, after, until). [2007 Framework 4e] Math Framework 4e: Use the calendar to determine past and future days. [2007 Framework 4h] National Standards addressed: Math Standard: Data Analysis and Probability Math Standard: Measurement Math Standard: Communication

Materials: Lyon Turn-X incubator with automatic turner Incubation Calendar handouts Incubation Calendar Cut-outs handouts Incubation Worksheet Computer and projector Scissors Glue Fertilized chicken eggs Cardboard box Newspaper Heat lamp Chick feed Small bowl Marbles Incubation PowerPoint Background: Chickens and other birds reproduce by laying eggs. Unlike mammals, in which the young develop in the mother s womb, female birds lay eggs and then care for them outside their bodies while the embryos inside the eggs develop. Only fertilized eggs can develop into baby birds. Chickens lay eggs whether the eggs are fertilized or not. These unfertilized eggs are the eggs that may be purchased in the grocery store to eat. The process by which a fertilized chicken egg develops into a baby chicken is called incubation and usually takes about twenty-one days. During incubation the mother chicken must keep the eggs warm and turn them regularly. If the eggs are not kept warm enough, the embryo inside the egg will die. If the eggs are not turned regularly, the embryo will stick to the side of the egg and will not develop properly. A fertilized chicken egg consists of several parts. The central part of the egg is the yolk. The yolk provides nutrition for the growing embryo. As the embryo develops, the yolk will become smaller and smaller. Fertilized eggs have a central spot on the yolk called the blastoderm. This part will grow and develop into the baby chicken. The albumen is the white part of the egg surrounding the yolk. This part of the egg contains coiled structures called chalazae that hold the yolk in place in the egg. Between

the albumen and the shell there is a small air sack. This will provide air for the growing chicken when it begins to breath with its lungs just before hatching. The head of the chicken develops so it is pointed toward this air sack at the large end of the egg. The egg s shell is the hard membrane that surrounds and protects the egg. The egg can absorb air and moisture through the shell. Some changes in the egg begin as soon as it is fertilized, but development ceases unless the egg is incubated. Within sixteen hours of beginning incubation, it is possible to see the first signs of embryonic development. The vertebrae, nervous system, head, and eye all begin to form within the first day. By the end of the second day the heart has formed and begun to beat. The legs and wings begin to develop on the third day. By the fifth day it is possible to determine the sex of the chicken; by the eighth, feathers have begun to form. On the thirteenth day the claws develop, and both the claws and beak begin to harden. On the fourteenth day the embryo gets into a position suitable for hatching. On the seventeenth day the beak turns toward the air sack. By the twentieth day the chicken embryo occupies almost all of the space within the egg, and the egg yolk begins to be drawn inside the chicken s stomach. Finally, on the twenty-first day hatching begins. Classroom incubation replaces the hen with an electronic incubator. The incubator must provide an environment suitable for the eggs development in the same way that a mother chicken would. The three important aspects of this are temperature, humidity, and motion of the eggs. An incubator must keep the eggs warm and provide the correct amount of humidity. An automatic turner can be used to turn the eggs. Even if all the proper precautions have been taken and the incubator operates correctly, it is highly unlikely that all the eggs will hatch. The success rate of the average hatch can be anywhere from 50%-90%. Taking proper precautions and operating the incubator correctly can increase the hatching rate, but it is not expected for all the eggs to hatch or for all the chicks to survive. Hatching should begin on about the twenty-first day after the eggs have been placed into the incubator. (Automatic turnings should have stopped three days before this.) The chicks will begin to break out of the eggs using the shell tooth on their beaks. It is important that the chicks be allowed to work their way out of the eggs on their own and without help. If a chick is not strong enough to emerge from the egg, it will not be strong

enough to survive. The process of the chick breaking free of the egg is a long process and is likely to take several hours. Once the chicks have hatched, they should be kept in the incubator for at least a day to rest and allow time for their feathers to dry. The chicks can survive for a few days without food or water, because they are still feeding on the yolk that has been absorbed into their stomachs from the eggs. After the chicks have had time to rest and dry in the incubator, they should be moved to a brooder. A brooder can be constructed using a cardboard box lined with newspaper and a colored heat lamp. The goal of a brooder is to keep the chicks in an environment where the temperature is controlled in order to slowly acclimate them to lower temperatures. After allowing the brooder to be heated by the heat lamp, move the chicks from the incubator to the brooder. The chicks should have enough room so they can move closer to or farther from the heat lamp as they desire. They should also be provided with water and feed. Every few days the temperature in the brooder can be lowered slightly by moving the heat lamp farther away. The newspaper should be changed when necessary to remove waste. When the chicks can survive at room temperature, they can be taken to their new homes. The heat lamp should be colored so the chicks do not damage their eyes looking at it. Procedure: Note: This procedure assumes that a Lyon Turn-X incubator is being used. Remember to consult the instruction manual of whatever incubator you decide to purchase. Whatever the incubator used, the outline in the procedure below should aid in a successful incubation project. 1. Before obtaining the fertilized eggs for this incubation activity, make arrangements with a local farm or collective to provide a home for the baby chicks once they hatch. 2. At least two days before the eggs arrive, choose a location for the incubator. The incubator should be placed in a location where the temperature will not fluctuate a great deal and where it will not be moved. It should not be in direct sunlight or near drafty doorways. 3. Fill the fountain (water bottle) with water. Place it upside down in the socket on the incubator. The water will flow out of the bottle, filling

one of the reservoirs and wetting the wick of the wet bulb thermometer. 4. Plug in the incubator. The heating indicator should light up on the incubator s top. This indicates that the incubator is heating. After several minutes, check the temperature. 5. If the temperature does not read 100 degrees Fahrenheit, use the dial on the top of the incubator to adjust the temperature. Turning it counterclockwise decreases the temperature, and turning it clockwise increases the temperature. Adjust the knob until the temperature remains steady at 100 degrees. 6. Five minutes after attaining a steady 100 degree temperature, check the temperature reading on the wet bulb thermometer. For the correct level of humidity, the wet bulb thermometer should read 86 degrees Fahrenheit. To increase the humidity and lower the wet bulb temperature, hold the nut at the base of the fountain and turn the fountain one-half turn counterclockwise. Wait another five minutes and read the temperature on the wet bulb thermometer. Repeat as needed until the temperature on the wet bulb thermometer is the desired 86 degrees. 7. Over the next two days check the incubator periodically to make sure the temperature on both thermometers remains constant. The heating indicator light will go on and off as the thermostat regulates the heater, but the temperature should remain constant. 8. Connect the automatic turner to the incubator by inserting the L- shaped hooks into the appropriate holds on the base plate of the incubator opposite the fountain. Connect the automatic turning arm to the dome of the incubator by hooking the arm over the knob on the incubator dome. Plug the automatic turner into the top of the incubator and hold down the red button on the automatic turner to ensure that the arm and the dome will rotate freely backward and forward. 9. If the eggs that are to be used have been stored in cool conditions, allow them at least twelve hours to warm to room temperature before placing them in the incubator. Remember to wash your hands before handling the eggs.

10. Place the eggs in the incubator with the small end pointed toward the incubator s center. The eggs should be resting as they normally would on a flat surface, with the large end slightly higher than the small end. The incubator should hold eighteen eggs. 11. If desired, use a pencil to mark some of the eggs with an O on one side of the egg and an X on the opposite side. This will indicate whether the automatic turner properly turns the eggs. 12. The eggs are now ready to incubate. Periodically check to see that the temperatures on the thermometers are constant and that the automatic turner is still functioning, but do not move the incubator or handle the eggs more than necessary. 13. On the day of the lesson, explain to the students that you will be discussing incubation. Tell them that incubation is the process in which a chicken embryo develops into a baby chicken. 14. Tell them that this process will be used to help practice time words like before and after and to help practice using a calendar. 15. Ask them what word they would use for something that happened first in time and what word they would use for something that happened next in time. For example, ask them whether they woke up and got ready BEFORE or AFTER they came to school. Which of these happened first? Which happened second? 16. Ask the student what they think comes first: an egg or a baby chicken. Does the egg come BEFORE or AFTER a baby chicken? 17. Show the students the Incubation PowerPoint, paying close attention to the BEFORE and AFTER words. 18. Explain that a fertilized egg develops into a baby chicken through a process that includes many different steps. 19. Tell the students that they will be working together to order the stages of the chicken embryo s development. Tell them to pay close attention to words like before, after, and during. 20. Distribute the Incubation Calendar handouts and cutouts. Help the students label the month template with the month that incubation will take place. Fill in the days according to that a month. (Note: if incubation begins after the ninth or tenth day of the month, two calendar handouts will be needed for each student.)

21. Explain that incubation takes twenty-one days. With the students, mark the day that incubation began by gluing the appropriate marker on the calendar. Help them count twenty-one days after that and mark the day incubation should be finished. Have them glue the correct picture on that day. 22. Have the students fill in the days of incubation between the day it starts and the day it is scheduled to finish by cutting out the rest of the cutouts and ordering them correctly on the calendar. Alternatively, cut out one egg outline each day and paste it on the calendar to show what the embryo looks like on that day. 23. Distribute the Incubation worksheet, and help the students complete the worksheet questions to practice reading a calendar and using the terms before and after appropriately. 24. Keep the completed Incubation Calendar on hand to refer to throughout the incubation period. Periodically ask the students to describe what the embryos look like on that day. Ask them what the embryos looked like before and after that day. 25. Be sure to deactivate the automatic turner on the eighteenth day of incubation. 26. As the twenty-first day of incubation approaches, explain to the students that not all the eggs will hatch on that exact day. Some may take a day longer or some may hatch a day earlier, and some many not hatch at all. 27. Record the number of eggs that begin to hatch on each day. With the students, use the attached Egg Cutout Sheet and the Hatching Graph to create a picture graph that shows the number of eggs that began hatching on each day. 28. Ask the students which day had the most hatchings. Which day had the least? 29. When the eggs begin to hatch, explain to the students that the chicks cannot be touched or helped out of their eggs. It may take the chicks several hours to free themselves from the eggs. 30. Allow the chicks to remain in the incubator for at least twenty-four hours before moving them. They will not need food or drink during this period.

31. Prepare a brooder for the chicks. A simple brooder can be constructed with a cardboard box lined with newspaper and heated at one end by a colored heat lamp. The heat lamp should be colored or tinted so the chicks do not damage their eyes looking at it. 32. Make sure there is variation of temperature in the brooder so that the chicks can move toward or away from the heat of the lamp if they desire. The point of the brooder is to slowly acclimate the chicks to lower temperatures. After all hatched chicks have been in the brooder for 24 hours, the temperature should begin to be decreased very slightly each day by dimming the heat lamp or moving it further away from the brooder. A good rule of thumb is to decrease the temperature by one degree per day until room temperature is reached. 33. Provide feed and water for the chicks in the brooder. Be sure that it is not placed directly underneath the lamp. To prevent drowning, put marbles in a shallow container of water so the chicks can drink from between them. 34. When the chicks are able to survive at room temperature, they can be taken to a local farm or collective. Evaluation: The students create their Incubation Calendars and can use them to read off the date when the incubation began and the date the eggs should hatch. They complete the Incubation worksheet and can explain the process of the embryo s development using before, after, and during. Extended Activities: If the students are curious about where the eggs come from and where the chicks will go, organize a field trip to a local farm. A good opportunity to do this would be when the chicks are ready to be taken to a farm. Bring the class along to see where the chickens will live.

Sources: Chickscope. University of Illinois. 1998. Accessed December 14, 2006. <http://chickscope.beckman.uiuc.edu/explore/embryology/> Egg and Embryo Development. Enchanted Learning. Accessed December 14, 2006. <http://www.enchantedlearning.com/subjects/birds/info/chicken/egg. shtml> Hatching Manual. Lyon Electric Company, Inc. Chula Vista, CA. July 1996. Leung, Michelle. Chicken Embryo. Rochester Institute of Technology. Accessed December 15, 2006. <http://www.microscopyuk.org.uk/mag/artnov04macro/mlchicken.html> Learn More About Eggs: Basic Egg Facts. American Egg Board. October 23, 2006. Accessed December 15, 2006. <http://www.aeb.org/learnmore/eggfacts.htm> Poultry: Stages in Chicken Embryo Development. Mississippi State University Extension Service. September 12, 2006. Accessed December 14, 2006. <http://msucares.com/poultry/reproductions/poultry_chicks_embryo. html> Wanek, Nancy. Chicken Embryo Development. Accessed December 14, 2006. <http://www.rit.edu/~nlwsbi/embryos.htm> Prepared by: Stephen Case NSF NMGK-8 University of Mississippi December 2006

MONTH: SUNDAY MONDAY TUESDAY WEDNESDAY THURSDAY FRIDAY SATURDAY 10

Incubation Calendar Cut-outs Cut out the pictures and put them in the correct order on your incubation calendar to see when the baby chicks will hatch. Day 1: Day 2: Day 3: Day 5: Day 8: Day 10: Day 12: Day 14: Day 16: Day 18: Day 20: Day 21: 11

INCUBATION WORKSHEET Answer the questions below as your teacher instructs. 1. We started to incubate our eggs on. 2. It will take our eggs days to hatch. 3. Our eggs should start to hatch on. 4. A baby chicken comes BEFORE / AFTER the egg. 5. The embryo hatches from the egg BEFORE / AFTER it has grown large enough to fill the egg. 6. The embryo must fully develop BEFORE / AFTER the egg hatches. Decide which picture in each pair comes first, and which comes after. Write BEFORE and AFTER underneath the correct pictures. 7. 8. 12

Egg Cut-outs (for Egg Hatching Graph) 13

Egg Hatching Graph Eggs Hatched 19 20 21 22 23 Day 14