1.All birds lay eggs.But just as birds differ very much in size，so do their eggs.The eggs of the little humming-bird areno bigger than peas，while each egg laid by the ostrich①is as bigas twenty-four hen‘s eggs.
2.In spring the wild birds of our woods and hedges build neat little nests of twigs and hayand straw，and line them with wool and feathers.Then they lay their eggs；sometimes only two or three，and sometimes twice as many，in each nest.These eggs are nearly always beautifullymarked with various②colours.
3.We should hardly think it possible that any child would like to rob the birds of their pretty eggs，and yet many children are wicked①Ostrich，the largest of living birds，is a native of Africa.It is famous for its speed in running，and for its valuable feathers.
②Various，different.
enough to do so.The eggs are of no use to the children，and are soon broken and lost，while the birds miss them very much.
4.But with our tame fowls it is quite different.We make nests for them，and feed and care for them，and they lay so many eggs that they do not show any signs of distress①when we take themaway.Wild birds lay only a few eggs during the spring，but hens lay eggs nearly all the year round.
5.Let us look well at a hen’s egg.Its colour is white，and its surface is full of very small holes or pores.These pores let in air for the chick inside to breathe.
6.The egg is oval in shape，but it is more pointed at the one end than at the other.This shape prevents②it from rolling out of the nest so easily as it would do if it were shaped like a ball.Theoval shape also makes the egg very strong.A man may squeeze the ends of an egg as hard as he can between the fingers and thumb of one hand without breaking it；but it is easily broken by pressing on its side，or by a sudden tap.
7.The shell is made of lime③，and is very brittle④.If you do notoften give your hens some pieces of chalk or of lime to peck，they will very likely sometimes lay eggs without any shell at all.
8.If you hold a fresh egg up to the light，you will see a small dark space just within the shell at the broad end of the egg.This space contains air.The egg-shell is lined with a thin skin，which is double at the broad end of the egg，and the air-space or air-chamber lies between the two layers of skin.
9.Next to this skin comes the “white，”which is a clear but somewhat yellowish liquid.In the middle of the egg is the yolk，which is coloured yellow by the oil or fat which it contains.
①Distress，pain；sorrow.
②Prevents，keeps from；hinders.
③Lime，a kind of earth got from burnt limestone.
④Brittle，easily broken.
10.This yolk is enclosed①in a bag made of very thin skin.Prick the yolk-bag，and the yellow stuff in it will run out very quickly.The yolk-bag is hung up，as it were，in the middle of the eggby means of two twisted whitish cords，which are fastened to the skin at each end of the shell.