Chicken coops plans

Laying an EggAn interesting event! By Wiebe H. van der Molen (molrenku AT diva.nl)

In books on poultry you can find how the egg is formed in the hen and howthe young develops within. But almost nothing is written about oviposition.In wildlife films on TV you see birds nesting, brooding, the chickens hatchingand being fed by their parents, but never I saw a bird laying an egg.

So I looked for myself. It is not easy to see what really happens, and Idid not understand what I observed. So I asked the Poultry Research Institutein Beekbergen for advice. Mr. Teunis showed me a video, explained the processand introduced me to the literature.

It appeared to be far more interesting than I supposed at first. In thefollowing, I will try to describe and explain what a laying hen does, five,six, even seven times a week.

Chickens never lay more than one egg per day. As a rule, chickens lay inthe morning, but each day a little later. Sometimes the last egg of a seriesis produced in the early afternoon. When it gets too late, they take thenext day off. My five commercial hybrids will sometimes lay for a seriesof 30 days or more.

Our Perspective on Laying Eggs (own observations, videoSpelderholt):

1. The hen approaches the nest in a very hesitant way, and finally enters.There she sits quiet for a long time, often for half an hour or more. Shecloses an eye or calmly puts a straw on her back, but finally she gets moreexited. Now and then, the hen raises her tail and spreads the feathers ofher bottom. These movements increase gradually.

2. Under her tail, between the feathers, is a small opening in the form ofa horizontal slit, about an inch wide. It is surrounded by a ribbed rim,with skin and feathers further outside. It is called the vent.

3. Suddenly the hen stands up with her feet wide apart, tail raised, bottomfeathers spread out, and back feathers upright. As her vent opens a little,you begin to see a red membrane.

4. As the hen lowers her bottom, her vent widens rapidly and the rim is stretchedfurther. The membrane forms a pinkish dome around the egg which is not yetvisible at this stage.

5. The vent is now wide open and the ribbed rim has become narrow and farstretched. Through the opening bulges a pink hemisphere of tissue revealingdistinct blood vessels. Its top is pointed downward where a new opening arises.The egg appears as a much lighter-colored disk. Even brown eggs are muchlighter than the surrounding membrane.

6. The hen strains at intervals. Each time, the egg comes a little furtherout. As it does, the membrane opens to form a red collar around the wider,middle portion of the egg. The membrane will protrude a little ways fromthe ribbed rim.

7. The moist egg pops out. Sometimes it will come out blunt end first, sometimespointed end first. For a few seconds after the egg is laid, a small red conestill remains outside, but it is retracted almost immediately and the ventis closed again. The bird stands high above the egg and rests, beak openand panting after the heavy work.

The entire process (from rising to dropping the egg) is quite fast and isfinished within half a minute. Therefore, it is hard to observe. After awhile, the hen looks back, inspects the egg with her beak and leaves thenest under loud cackles. The hen then eats and drinks and goes her usualways. She seems to have forgotten her egg completely.

The Hen’s Perspective on Laying Eggs (Wieckmann, 1896; Grzimek,1964):

1. Chickens, as well as other birds, have a common openingfor reproduction, and for the evacuation of stools and urine. This openingis called the “vent”. They do not have a bladder because their urine is nota fluid. It is a white paste, called urates, that you can observe surroundingthe droppings. The intestine, ureters and oviduct come together into a commonchamber called the cloaca. This is a rather dirty place, whereas the eggis always clean and almost sterile when laid.

2. The henturns part of the cloaca and the last segment of the oviduct inside out,”like a glove.” The described red membrane is then everted inside of theseorgans. The egg emerges far outside, at the end of the bulge. So it cannotcontact the walls of the cloaca and get contaminated by stools or urine.Moreover, the intestine and inner part of the cloaca are kept shut by theemerging egg, and their contents cannot leave when the hen strains to deliverthe egg. Therefore, eggs are always clean as they are laid. However, sometimesa hen, stomping around the nest with dirty feet, will get the egg dirtyanyway.

Why Chickens Leave the Nest

All chickens lay eggs in a series – never more than one per day. If the eggsare not collected, and a sufficient number of eggs are allowed to remainin the nest, the hen may stop laying eggs and start brooding. When the henleaves the nest after laying an egg, it cools which suspends the developmentof the embryo inside. If the ambient temperature remains between 45F and65F, the embryos will remain viable for as long as two weeks. When the henbecomes broody and sits on her eggs for three weeks, all of the eggs willhatch at about the same time. This is why it is important for the hen toleave the nest after laying.

Breaking Broodies

When we remove the eggs, the hen supposes: “There are not yet enough,” andcontinues to lay. The hens of some breeds will get broody anyway after sometime. This condition can be cured by placing the hen in a “broody pen”. Thisis a small cage, hung in the hen house. The cooling of the bottom, the swingingmovements, and the lack of eggs to sit on are said to cure this condition.The broodiness trait has been removed from most commercial laying breedsthrough selection. The modern laying hen has delegated her responsibilityof hatching, raising, and educating chicks to humans. In nature, the poorcreatures would soon become extinct.

The Story Behind the Hen’s Cackle

Wild chickens are forest animals. They live in small groups called flocks.They scratch in the dirt and forage for things to eat. While one hen sitson the nest to lay, the group may wander away through the undergrowth searchingfor food. The hen’s cackle serves to renew the contact with the group asif to yell “where are you?”. The cock (with the other hens) answers “herewe are!”.

References:1. Own observations.2. Video and explanation by Mr. Teunis, Het Spelderholt, Beekbergen.3. Tukker, J.G. & P.E. Rijpma, 1953. Het Ei bij de pluimveehouder enbij de verzamelaar. 79 pp.4. Grzimek, B. & F. Pusch, 1964. Das Eierbuch. 7-e Aufl., 1964, 220 pp.(the figures on p.3).5. Wickmann, H., 1896. Die Lage des Vogeleies im Eileiter vor und währendder Geburt. Journ. f. Ornith. XLIV, 81-9

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