Where do baby chicks come from?
Those cute, fluffy baby birds recently hatched out of eggs! How did they live in their eggs? How long did it take for them to get out of the eggs? Keep reading to find out!
The Case of the Disappearing Eggshell
An egg is covered by a hard shell to help protect the chick growing inside. When the chick is ready to hatch, it breaks the shell open. Try this experiment to find out what a shell is made of:
What You Need:
- An egg from the grocery store
- A drinking glass
- White vinegar
What You Do:
- Set a raw egg in a glass of white vinegar so that it’s completely covered in the liquid. Bubbles should start to form on the surface of the egg.
- Let the egg sit in the vinegar for about 3 days and then take it out and rinse it in water, being careful not to pop it. Does it feel different from when you put it in the vinegar? Does it still have a white shell?
The eggshell disappeared! But there might be some chalky white stuff left on the egg. This is because vinegar is a type of acid that “ate” away and dissolved the calcium carbonate that the shell is made out of. (Chalk is also made out of calcium carbonate!) When something dissolves, it breaks into very tiny pieces and mixes with a liquid. You can see it happening if you put a sugar cube into a cup of hot water and stir. The sugar cube disappears as the sugar dissolves into the water.
You might be wondering why the egg white and yolk inside the shell stayed in the shape of an egg even though the shell is gone. This is because the egg has another covering underneath the shell; called a membrane. It is very thin and you can see the yellow yolk through it. The vinegar can’t dissolve the egg membrane, but some of it was able to get through the membrane, making the egg swell up.
In the last project, the egg membrane let liquid in, making the egg swell a little bit. Do this project to see if you can get the egg to shrink!
What You Need:
- The egg without its shell from the previous project
- A drinking glass
- Corn syrup
What You Do:
- Carefully place the egg in a glass of corn syrup, so the egg is covered.
- Let the egg sit in the corn syrup for about 3 days. Then take it out and see what happened!
The egg shrank! This is because the egg membrane let a bunch of water pass out of the egg to try to balance how much water was inside the egg and how much water was outside it in the glass. The very tiny parts that make up corn syrup (called molecules) were still too big to pass through the membrane, so none of the corn syrup got inside the egg. The egg lost a lot of water, but didn’t get anything to take the water’s place, so it looks a little funny! Do you think it would fill up again if you put it in a glass of water? Try it out!
The fact that the egg membrane can let some things through is very important for a baby chick. Air passes through the membrane, just like water did in this experiment, and that allows the baby chick to breathe while it’s inside the egg.
When baby chicks hatch, they are covered with tiny, soft, fluffy feathers called down. Down helps keep them warm. (It can keep us warm too, which is why quilts and coats are often stuffed with down!) As they grow older, chicks grow bigger feathers called contour feathers. These are colored on the tips and downy at the base (the part closest to the body) to help keep them warm. They also grow long, strong flight feathers on their wings and tail. Look at a feather up close to learn more about it:
What You Need:
- A large feather (you can try to find one outside, or buy one from a craft store. Feathers you find outside can be very dirty, so make sure you wash your hands when you’re done with this project!)
- Magnifying glass
What You Do:
- Feathers help protect birds from getting drenched in the rain. Instead of soaking through them, water just slides right off! Turn on the water faucet so it is just a tiny trickle. Hold a paper towel underneath the faucet and watch how the water soaks right through. Next, put the feather under the trickle. What happens? The water should just roll off, leaving the feather dry. (If it doesn’t, try turning the feather over.) Birds keep their feathers waterproof by putting a layer of oil on them. They get the oil from a place near their tail called a preen gland.
- Look at a piece of velcro. Do you see how one side has tiny hooks that catch on to the other side? Bird feathers work a little bit like this. Take your feather between two fingers and rub your fingers down from the tip. The long, thin “branches” of the feather (called barbs) will separate into sections. Use a magnifying glass to look at the barbs: they are covered with tiny little hairs called barbules. Now take your fingers and smooth the barbs back together. The barbules catch each other and stick, like velcro. Sometimes you will see a bird rubbing its feathers with its beak. This is called preening and the bird does it to smooth the barbs back together.
- What’s that running down the middle of your feather? That’s the rachis (say RAY-kuhs), and it makes the feather strong. Look at the very end, which is called the quill – does it look a little bit like a drinking straw? That’s because it’s hollow, to keep the feather from getting too heavy. People used to dip the quill in ink to use as a pen!
All About Chickens
How a Chick Hatches
A mother chicken is called a hen. The baby chick’s life cycle starts when its mother hen lays an egg. This egg has a big yellow yolk that contains all the food the chick needs while it grows inside the egg. The yolk floats in the egg white, which protects it and contains water for the chick. For about 21 days the hen sits on her eggs and covers them with her feathers to keep them warm. Several times a day she turns the eggs with her beak. She does this to keep the yolk from sinking down and crushing the chick against the shell.
When it is time for the chick to hatch, it pecks holes in the shell with a bump on its beak called an egg tooth. A few days after the chick has hatched, the egg tooth falls off because the chick doesn’t need it any more. The chick in the picture still has its egg tooth. The chick has to take lots of breaks to rest, and when it finally gets out of the shell it doesn’t get up and move right away — it’s too tired! Its feathers are wet and stringy, but they soon dry and become fluffy.
Baby chicks grow up fast. Young girls are called pullets and young boys are called cockerels. Pretty soon they will be grown-up hens and roosters and start having their own babies!
All birds lay eggs, but they don’t all do it in just the same way:
- Most birds build nests out of twigs and grass or mud. These keep the eggs and chicks protected from other animals who might want to eat them. Many birds build their nests in trees, but some build them on the ground.
- Emperor penguins live in snow and ice and don’t have anything to build their nests with. They only lay one egg, and to keep it warm they balance it on top of their feet under their feathers for two whole months!
- Some cuckoo birds don’t build their own nest or take care of their own chicks. They lay their eggs in the nest of another bird and let that bird take care of them.
- Swiftlets in Asia build their nests on the ceilings of caves. They build them out of their own spit! People in Asia sometimes cook these nests to make bird’s nest soup.
Eggs come in lots of different colors and sizes. A hummingbird egg is the size of a jelly bean. A robin egg is blue and about the size of a quarter. Ostrich eggs are the largest; they are bigger than a grapefruit!
There are lots of different names for baby birds! In general, they are called chicks or hatchlings, but some types of birds have special names. Here are a few:
- A baby duck is called a duckling.
- A baby goose is called a gosling (say GOZ-ling)
- A baby eagle is called a fledgling or an eaglet.
- A baby swan is called a cygnet (say SIG-net) or a flapper.
- A baby pigeon is called a squab (say SKWAHB).
Groups of hatchlings are sometimes called a brood or a clutch. Groups of grown-up birds can have different names, too. Usually they are a flock, but a group of geese is called a gaggle and a group of ducks is called a brace.
Down – tiny, soft, fluffy feathers that keep the chick warm.
Hen – a grown-up, mother (female) chicken.
Yolk – the yellow part of the inside of the egg. This gives the baby chick the food it needs to grow.
Egg Tooth – a bump on the chick’s beak that it uses to crack the shell so it can hatch.
Print out this coloring sheet to help kids match the baby birds with their parents!