万思乐学V-learn小西妈妈双语工程2002期, 02号Jeremy ,打卡Day2020

Jane Liu-晴雨🍒

💽Listening:

   Peppa pig, Oxford reading tree 9

🖥Video: 

   Peppa pig 2 episodes

   Curious George 2 episodes

   Kinderpower 3A unit7

📚Reading

Hatch chicks and ducklings

Chick embryo development

Days 1 and 2 of incubation see the start of growth for everything of huge importance to the embryo.

The head, ears, eyes, spinal column, nervous system (including the brain) and heart begin to develop.

As early as 72 hours after the start of the process, tail, wing and leg buds appear and the heart begins to beat.

By day 4 the toes and tongue have begun to form (yes, chickens may not have teeth but they do have a tongue!) and on days 5 and 6 the crop, reproductive organs and beak start forming and the wing can now bend.

By day 5, you'll be able to see the chick developing when you candle the egg.

Inside a hatching egg day 5

The allantois is part of what in a human embryo we would call the umbilical cord and is responsible for getting rid of waste as the chick grows.

You'll quite often see be able to see it left behind in the shell after the chick has hatched.

The amnion or amniotic sac is a membrane which surrounds and protects the embryo during its development.

On day 7, the leg is able to bend and a ridge of 'papilla' or glands form where the the feathers will appear on the tail and thigh.

By the end of this first week, your chick is one third of the way to full development.

Days 1, 2 and 3

There's really not much to see at this point. Initially the egg will look clear apart from the air cell which you'll see at the 'fat' end of the egg. As time goes by you'll notice this air sack become larger and it's here the chick will eventually hatch.

From day 2 to 3 

you'll be able to see the yolk of the egg. When I first saw this, I was hugely excited - I thought it was the embryo. That's how much I knew.

Days 4 and 5.

From about day 4 or 5 in a properly developing egg you'll start to see tiny spider like markings appearing in the yolk area when you candle your eggs.

These are easiest to see in white or light-coloured eggs - in a dark-coloured egg like a Marans they're much more difficult to spot.

This is the start of the embryo's visible development. The 'spider legs' you can see are the embryo's blood vessels, which will become much more well-defined over the next several days.

Days 6 and 7.

The next few days see the development of the blood supply to the developing embryo, and the eye becomes far more prominent too.

If you look closely, you can see the outline of the embryo developing - it looks like a darkish ring around the eye.

Also notice at the bottom of this picture that the air cell has started to get a little larger. This too will become more obvious with time.

Day 8.

By the start of this week the embryo will be clearly visible when you candle the egg. The eye will become more prominent with time but even at this stage it can be clearly seen - look for a large black dot. 

Day 9

The eyes are now also very clearly visible as dark blotches. Sometimes you can only see one, sometimes two - it depends which way the chick is lying.

Day 10 and 11

This is an important part of the embryo's growth. It gets rid of waste products in much the same way as the umbilical cord in a human embryo. Without it, the egg would die.

Day 12

The chick is doing more of the same. You may be able to see it moving about inside the egg although, as it grows, it has less room to wiggle around.

Day 13

The other side of the egg is now full of chick so just looks dark. 

The veins are developing nicely. This is a strong, healthy chick!

Day 15

You can see here how the embryo is now filling a large part of the egg. 

Day 16

The embryo is now so big that the top part of the egg looks completely dark and only a few veins are visible at the air cell end.

Day 17

Only twenty-four hours later, even less can be seen. The chick is now filling all but the very extreme end of the egg.

Day 18

This picture shows the air cell very clearly but not much else. The air cell by now has grown enough to allow the hatching chick to take its first breath there. The chick is filling the entire rest of the egg.

Day 19

There are no further candling photographs after this point because the eggs need to be left alone so the chicks can properly position themselves for hatching. They will remain untouched in the incubator until the chicks are hatched and dried.

Day 20

On day 20 the yolk finishes being absorbed fully into the chick. This is what makes it possible for hatchlings to be able to survive without food or water for several hours. 

The beak is poised to start pecking through the shell and, apart from the air cell, the embryo is completely filling the egg.

As the 'egg tooth' starts to penetrate the membrane, the lungs are fully working and breathe in that all-important air from the air cell.

Day 21

Day 21 - for the most part - is hatch day, although some chicks hold on and don't hatch exactly on time. Chicks will hatch when they're fully developed, and when the yolk has been absorbed into the chick's body.

So don't worry too much if they're late hatchers, and don't try to open the shell. Doing so before the yolk is completely absorbed will kill the embryo.

If all is going to plan, the chick now begins to do some serious 'pipping', or breaking through. It uses its wing as a guide and its legs to propel it, working in a circular motion to create a hole which will eventually be large enough for it to squeeze its legs through and push!

Drawing a chick house

第1次孵蛋，经验不足，孵化率很低:

9个鸡蛋，出了4只小鸡

6个鸭蛋，出了2只小鸭，有一个都已经开壳了，没有成功出壳，闷死在里面了，非常可惜

这对孩子是个非常好的体验，明年继续，孵鸟蛋😁