Embryology 101 - Lesson 2 - Inside the Egg

Elizabeth Janning, Melissa Mracek, Sarah Paisley, and Melinda Vlieger Author

02/24/2021 Added

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This is the second lesson out of four from the Embryology 101 Curriculum. In the manual, this is lesson 3; however, since we candle eggs at day 9 we utilized this lesson second.

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[00:00:00.637](upbeat music)
[00:00:08.530]Hello again and thank you
[00:00:09.990]for continuing with us on our exciting journey
[00:00:12.290]as we learn more about embryology
[00:00:14.550]through the Nebraska 4-H Embryology 101 program.
[00:00:18.900]This is the second
[00:00:20.080]of four lessons that will guide you through the development
[00:00:22.670]of embryos and chicken eggs.
[00:00:25.170]As I said in our last video, my name is Sarah Paisley
[00:00:27.910]and I am the extension educator
[00:00:29.470]for Gardner and Morrill Counties.
[00:00:31.130]I am excited to be your co-host again
[00:00:33.000]as you continue this virtual journey of embryo development.
[00:00:36.780]Today, I will be joined by Melissa Mracek,
[00:00:39.520]who is the 4-H educator for the Northern Panhandle.
[00:00:43.070]She has some exciting videos for you today
[00:00:45.970]as we check on her eggs inside of the incubator.
[00:00:49.550]Before we would start with our lesson though,
[00:00:51.750]I need you to get out your questions page
[00:00:54.240]from the last time we met.
[00:00:55.810]Remember the one I told you to keep in a safe place?
[00:00:59.240]At the end of the lesson,
[00:01:00.650]I asked you to add any more questions that you still had
[00:01:05.020]and to answer the ones
[00:01:06.940]we may have answered during the lesson.
[00:01:09.780]Do you still have a lot of questions left?
[00:01:13.320]Take a moment to reread them.
[00:01:15.720]Pause the video if you need to.
[00:01:20.560]Did looking at these questions
[00:01:22.920]spark up any other ideas or questions?
[00:01:26.970]Write it down if it did.
[00:01:30.380]We are actually going to look at another picture today.
[00:01:34.560]You are going to do the same thing.
[00:01:37.380]Write down any questions that pop into your head.
[00:01:41.170]Are you ready to write any questions
[00:01:43.330]that you have about this picture?
[00:01:45.970]Okay, here we go.
[00:02:34.640]Thanks for thinking about this picture today.
[00:02:37.220]Don't put this paper too far away
[00:02:39.000]as Melissa is going to ask you about it too.
[00:02:42.120]Before we actually introduce Melissa though,
[00:02:44.950]I want you to see our objectives for this second lesson
[00:02:48.190]which is called inside an egg.
[00:02:50.720]By the end of today,
[00:02:51.960]you will be able to identify the difference between an egg
[00:02:56.130]with a growing embryo inside compared to a non-fertile egg.
[00:03:00.290]And also explain why farmers and ranchers
[00:03:03.440]care for their animals.
[00:03:06.030]It is now my pleasure to turn this over to Melissa.
[00:03:11.990]Hi, I'm Melissa Mracek, a Nebraska 4-H and youth educator
[00:03:18.120]and I am so excited to have you join us
[00:03:20.130]on our embryology journey.
[00:03:22.820]Today, we're gonna take a look inside the egg.
[00:03:26.010]So if you're looking at your list of questions
[00:03:28.480]that you've developed at the beginning of this project,
[00:03:31.180]maybe one of those questions is how a chick grows
[00:03:35.750]or how does an egg turn into a chicken?
[00:03:38.290]Hopefully by the end of today's lesson,
[00:03:40.590]we will have those questions answered for you.
[00:03:43.730]Today, we are going to candle the eggs
[00:03:45.890]and talk about what needs done for the chicks
[00:03:48.420]the last few days before they hatch and after they hatch.
[00:03:53.240]How have we been taking care of the eggs so far?
[00:03:59.680]Well, so far, we've providing them with exercise.
[00:04:05.260]Our chicks have been rotated multiple times a day
[00:04:09.080]making sure that it is an odd number
[00:04:11.760]so that one side of the egg
[00:04:13.410]does not get hotter than the other.
[00:04:16.090]We've also been providing warmth at a constant temperature.
[00:04:20.560]The incubator is maintaining 100 degree temperature.
[00:04:25.570]We've also been maintaining humidity at 55%.
[00:04:30.130]We do this by adding water
[00:04:31.830]to the bottom of our incubator.
[00:04:34.930]Food, the yolk inside the egg
[00:04:36.930]provides the growing embryo with food.
[00:04:39.390]Right before it hatches,
[00:04:41.230]it will suck up the remaining part of the yolk
[00:04:43.390]into its stomach.
[00:04:44.980]This allows for the chick to be able
[00:04:46.800]to stay in the incubator for 24 to 48 hours
[00:04:50.250]after it is hatched.
[00:04:52.680]Air is provided through the pores in the shell
[00:04:55.890]and the air sack provides air for the embryo to breathe
[00:04:59.280]right before it hatches out.
[00:05:02.410]That's a lot of stuff
[00:05:03.330]happening inside the incubator,
[00:05:05.260]but it'd be even cooler to see what's happening
[00:05:07.790]inside of the egg.
[00:05:09.480]So right now, we're gonna take a few minutes
[00:05:11.290]to watch a video from Poultry Hub Australia
[00:05:14.680]to see just how that embryo changes,
[00:05:17.670]whether it's inside the incubator
[00:05:19.930]or incubating underneath the hen.
[00:05:24.609](calming music)
[00:07:27.303]That was a pretty cool video
[00:07:28.670]that showed a lot of development
[00:07:30.400]and I would actually encourage you to rewind
[00:07:32.980]and take a look at it again
[00:07:34.830]if you didn't catch some of those days
[00:07:36.980]that were being displayed there.
[00:07:40.470]What we ask for you to do right now
[00:07:42.230]is actually find your embryology journal
[00:07:45.980]that your teacher provided for you.
[00:07:48.060]You're gonna find the page called embryo growth chart.
[00:07:50.980]Inside of each of those eggs, we're gonna have you sketch
[00:07:54.410]what the embryo would look like on that particular day.
[00:07:59.030]So again, you might have to rewind the video
[00:08:01.560]in order to take a look and see
[00:08:03.620]what the embryo actually looks like
[00:08:05.570]and some of the big developmental things
[00:08:07.760]that are taking place on that day.
[00:08:14.740]And right now,
[00:08:15.573]I'm gonna go ahead and turn it back over to Melissa
[00:08:17.870]who's going to explain to us
[00:08:19.450]a little bit more about the importance of day 18.
[00:08:25.130]As you can see in the video,
[00:08:27.080]day 18 was a pretty big day for our growing embryo.
[00:08:31.380]For us, day 18 is a big day as well.
[00:08:35.070]On day 18, we will remove our egg turn
[00:08:38.180]that we are using to rotate our eggs.
[00:08:41.540]We will also add additional water to the bottom
[00:08:44.570]of our incubator to increase our humidity to 65%.
[00:08:49.570]The extra humidity is utilized to help our embryos
[00:08:53.530]or chicks get out of the shell when they are ready to.
[00:08:57.680]We're also going to take out of the plug of the top
[00:08:59.990]of the incubator to allow for additional air flow
[00:09:03.650]as the chicks begin to produce heat of their own.
[00:09:06.980]The final and most important thing
[00:09:08.320]is they're gonna close the lid
[00:09:09.600]until the eggs hatch and not open it again.
[00:09:14.410]We know their chicks are getting ready to hatch
[00:09:17.670]and they will use their egg tooth to start to crack the egg.
[00:09:22.670]It could take them anywhere up to 24 hours to hatch
[00:09:27.140]and we are not supposed to help them hatch up.
[00:09:30.100]They have a better success if we leave them alone
[00:09:32.520]and let them do it themselves.
[00:09:34.700]Once they hatch, the chicks will be wet and tired
[00:09:37.760]and we are to leave them in the incubator
[00:09:39.750]until they are dry.
[00:09:42.930]After a chick hatches,
[00:09:45.090]what do you think a chick will need in order to survive?
[00:09:49.970]Just like in the incubator,
[00:09:52.887]our chicks are gonna need some of the same things.
[00:09:55.540]They're going to need food, water, and shelter.
[00:09:58.560]They're also gonna need a few extra supplies.
[00:10:01.490]On a farm,
[00:10:02.323]the farmer would make sure that the chicks are cared for
[00:10:04.770]by providing them with food, water, and shelter,
[00:10:09.020]and we're gonna do the same thing.
[00:10:10.850]So the first thing that we're going to do
[00:10:12.400]is have a brooder house for our chicks to go into.
[00:10:15.670]This may be a cardboard box to protect the chicks
[00:10:18.850]from drafts and to keep them safe.
[00:10:21.540]It will need to be lined with wood shavings or newspaper
[00:10:24.650]to help prevent the chicks
[00:10:26.150]from slipping and hurting their feet.
[00:10:28.690]We have continued to provide heat with a heat lamp.
[00:10:32.370]This will keep the chicks warm
[00:10:34.290]as they still need to be under 95 degrees.
[00:10:41.070]If our chicks are all huddled into the light,
[00:10:42.830]then that means they're probably too hot or maybe too cold
[00:10:48.070]and if our chicks are spread out and not moving very much,
[00:10:53.090]that probably means that they are too hot.
[00:10:55.890]We are also gonna provide chick starter feeds
[00:10:58.150]that chicks will have something to eat
[00:11:00.080]and fresh water for them to drink.
[00:11:03.290]Chicks have an instinct to peck.
[00:11:05.550]So they quickly learn what their food is by pecking things
[00:11:09.140]and seeing if it tastes good like the food
[00:11:12.040]or if it tastes bad
[00:11:13.390]like our wood chips or newspaper clippings.
[00:11:17.660]So why is it important for us to care for our chicks?
[00:11:21.560]It's important because we get food like eggs
[00:11:24.080]and meat from them.
[00:11:25.770]We care about them just like farmers and ranchers
[00:11:28.020]care about the animals that they raised
[00:11:30.080]because they know that they're helping to feed the world
[00:11:32.830]and their own families.
[00:11:35.190]Here in a minute, we're going to candle our eggs.
[00:11:38.140]We're gonna look for eggs that are fertile,
[00:11:40.700]early deads or infertile.
[00:11:43.150]Fertile eggs have embryos that are developing.
[00:11:46.850]By this point, day nine,
[00:11:49.010]we should be able to see the eye and the shadow of its body.
[00:11:52.570]Early deads are embryos that have started
[00:11:54.760]but for some reason have died.
[00:11:56.830]And so that will be seen with their blood vessels
[00:11:59.810]being in a ring instead of in branched out form.
[00:12:04.090]Infertile eggs are eggs that never started
[00:12:07.540]or had the ability to develop into an embryo.
[00:12:12.240]So what type of eggs would you like to see the most of?
[00:12:16.980]Currently in our incubator, we have 33 eggs
[00:12:20.090]so I'd like you to pause this video for a minute
[00:12:22.710]and make a hypothesis or prediction
[00:12:25.370]of how many fertile, early deads and infertile eggs
[00:12:30.750]we will have in our incubator.
[00:12:34.830]Great, now that you have a hypothesis,
[00:12:36.710]let's actually take a look
[00:12:37.730]at what we are looking for inside of that egg.
[00:12:42.010]So on day one and day two,
[00:12:44.450]we really can't tell that there's much difference
[00:12:47.530]than the egg that I showed you last time.
[00:12:49.760]But on day three, we start to see
[00:12:52.240]that there are going to be some of those
[00:12:55.240]blood vessels forming.
[00:12:56.560]And of course on day four, they get bigger
[00:12:58.970]and we start seeing that embryo really developing.
[00:13:02.090]On day five and all the way into day nine,
[00:13:05.340]which is where we're going to check our eggs
[00:13:07.467]out here in just a few minutes,
[00:13:09.290]we can definitely see that there is an embryo developing
[00:13:13.710]and it's starting to actually look like a chick.
[00:13:16.610]We should have a beak,
[00:13:18.380]we should have these big black spots
[00:13:20.590]that look like eyes as we look inside of our egg.
[00:13:24.500]So we are going to switch it back over to Melissa
[00:13:28.030]so that she can explain a little bit more about candling.
[00:13:32.960]Does anyone know what candling is?
[00:13:35.980]Candling is the process of shining a light
[00:13:38.040]inside the egg to see its development.
[00:13:41.250]To candle the eggs,
[00:13:42.560]we're going to hold the larger end of our egg
[00:13:44.930]up to the light in a dark room
[00:13:47.630]and slowly turn it until we can see inside the egg.
[00:13:50.960]So this first egg is a fertile egg.
[00:13:54.490]As you can see, that dark spot is our eye of our embryo.
[00:13:58.790]And you can also see the outline of our embryo.
[00:14:01.370]Here in the top right are some of its blood vessels
[00:14:04.730]and they look like tree branches branching out.
[00:14:07.860]Like I said, you can kind of see the outline of our body.
[00:14:10.640]And it's about the size of a quarter.
[00:14:16.520]Kind of right there in the center of that egg moving around.
[00:14:22.960]Here is our next egg.
[00:14:26.240]This egg is infertile.
[00:14:28.970]It looks like a glowing sun
[00:14:30.820]and at the very top, that darker spot is our yolk.
[00:14:33.590]And as we rotate it around,
[00:14:35.180]we can't see any blood vessels or any embryo development,
[00:14:39.520]but however we can clearly see the pores
[00:14:43.000]that are on our egg shell
[00:14:44.870]that allows the air movement in and out.
[00:14:47.710]Our third egg is an early dead.
[00:14:50.570]As you can in that bottom part of our egg,
[00:14:52.700]we see a ring that is our blood vessel
[00:14:55.660]of the embryo that started to develop, but didn't.
[00:14:59.330]Up there at the top right
[00:15:01.030]is the part of our embryo that started to develop.
[00:15:07.810]For some reason it didn't survive,
[00:15:10.730]but it was a fertilized egg in the very beginning.
[00:15:16.780]So now we're gonna flip it over
[00:15:18.000]and kind of look at our air cell at the bottom of our egg.
[00:15:22.340]You can kind of see it's a lighter little pocket
[00:15:24.870]at the very bottom.
[00:15:29.700]Our next egg is a fertile egg.
[00:15:31.580]This one's a little bit harder to see
[00:15:32.880]as it may have been a darker shell,
[00:15:34.627]but at the top right is that embryo
[00:15:37.380]and the extra dark spot is the eye of our embryo.
[00:15:43.180]We're gonna rotate the egg
[00:15:44.410]to see some of the blood vessels that are developing.
[00:15:47.640]Again, these should be in a branch form
[00:15:50.370]and not in a circular ring.
[00:15:54.470]The yolk is kind of that darker bit
[00:15:57.290]that we see within inside our egg.
[00:16:01.210]This egg is an infertile egg,
[00:16:03.500]but you can tell this by the bright yellow
[00:16:06.130]and then that darker spot is the yolk within our egg.
[00:16:09.500]We don't see any blood vessels as we rotate it around.
[00:16:15.240]If we flip it over, we're gonna look at the air cell
[00:16:18.130]which is that little white pocket down there
[00:16:20.630]at the very bottom.
[00:16:24.100]And here's our last egg that we're gonna look at
[00:16:25.740]and this one is a fertile egg.
[00:16:28.000]We can see great blood vessels and that they look
[00:16:31.640]in a spider web form that branches out
[00:16:34.480]instead of being in a ring.
[00:16:36.750]At the top right is our embryo
[00:16:39.450]and you can kind of see it moving around on us as well.
[00:16:49.010]It continues to move around,
[00:16:50.330]but that dark spot in the middle is where its eye would be.
[00:17:00.210]We're gonna flip it over
[00:17:01.080]and look at our air cell in the bottom.
[00:17:05.640]So this is where our embryo is going to go into to breathe
[00:17:11.100]right before it hatches out of the egg.
[00:17:15.960]So I want you to take a minute and pause the video
[00:17:18.910]and write down what surprised you about today's lesson.
[00:17:22.560]The farmer was caring for the chicks instead,
[00:17:25.420]what would they do to care for the chicks
[00:17:27.680]and why would they do this?
[00:17:32.810]Also, now it'd be a good time to review the list
[00:17:35.330]of questions that you've created so far
[00:17:37.980]and add if you have new questions
[00:17:40.760]that of you have thought of.
[00:17:42.290]Hopefully you can check off that list that we have
[00:17:46.120]figured out how a chick grows
[00:17:47.900]and how an egg turns into a chicken.
[00:17:51.120]Some great activities you can do now
[00:17:54.030]is in your embryology journal,
[00:17:55.800]complete the what does an egg need page.
[00:17:59.820]Again, draw what the embryo looks like
[00:18:01.700]at five different days if you didn't already do this,
[00:18:05.480]and you can also create a graph of the number
[00:18:07.610]of fertile, infertile, and early dead eggs that we had.
[00:18:11.650]In our incubator, we had nine infertile eggs,
[00:18:17.070]17 fertile eggs and seven early deads.
[00:18:22.280]How does this compare to your prediction?
[00:18:27.500]We want to hear from you.
[00:18:28.420]We'd love to see what you're doing
[00:18:29.640]with your embryology project
[00:18:31.450]so feel free to send us pictures
[00:18:34.120]of your worksheets that you're doing
[00:18:36.430]and tag it to #NE4HEGGS.
[00:18:40.600]Thanks for joining me
[00:18:41.740]and I hope you continue on with our embryology project.
[00:18:48.590]Thanks Melissa for such an exciting lesson today.
[00:18:51.850]We have sure learned a lot, including the importance
[00:18:54.970]of taking care of eggs while they're incubating
[00:18:58.530]and taking care of the chicks afterwards.
[00:19:01.490]We learned how to take care for our eggs in the incubator
[00:19:04.410]after day 18, which is a huge difference in the other days.
[00:19:08.860]And we also got to do one of my favorite things,
[00:19:11.880]which is candling.
[00:19:13.970]We really have learned a lot
[00:19:15.570]so I want you to do one last look
[00:19:17.590]at your questions page today and take a look
[00:19:21.080]and see if there's any questions that we may have answered.
[00:19:25.130]Go ahead and take the time to write down those answers
[00:19:28.460]so that we can review them later.
[00:19:30.990]And as always, remember to keep this paper safe.
[00:19:35.750]We'll need it again for the next lesson.
[00:19:40.490]Thank you for joining us today
[00:19:42.020]on this second lesson of Embryology 101.
[00:19:45.490]We hope that you continue with the next lesson
[00:19:47.970]titled build a chick as you continue this virtual journey
[00:19:51.700]through embryo development.
[00:19:53.600]See you again on Embryology 101
[00:19:56.090]sponsored by Nebraska Extension.
[00:19:58.818](upbeat music)

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Embryology 101 - Lesson 2 - Inside the Egg

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