Do we really understand a hens egg laying cycle?

[Shadrach]

Ask what determines a hens egg laying cycle on most forums and you will most likely be told that it is governed by light levels. What exactly does this mean?
Some will state it’s a matter of the length of light hours.
Some suggest it’s the intensity of the light.
Some suggest that it’s a change in lights frequency range over the winter months.
It’s a common practice to add supplementary lighting in backyard coops and industrial coop units which apparently prolongs a hens egg laying cycle.

It is generally accepted that pullets will lay over their first winter assuming they reach maturity in the preceding months.
It was common knowledge until relatively recently that moulting was the cause of the cessation of the egg laying cycle. This has since been proven wrong but the myth endured for many years and is still cited today.
It’s December and the days are at their shortest by monthly sun cycles.

I have one 3 year old hen who started laying earlier this month, one 4 year old who started laying today and a two year old who is currently looking for a nest site indicating she will be laying soon.
I’ve had bantams that laid throughout December having had a break from late October to mid December.
Do we really understand the hens egg laying cycle?

 

[TheChiggens]

Well now im starting to question it...
How much research ahs gone into it?

 

[aart]

Do we really understand the hens egg laying cycle?

Nope, not entirely.
Lots of variables.
But folks will never stop trying to explain things.

 

[Ninjasquirrel]

Not a scientist here but my understanding is that a hen ovulates within 2 hours after an egg is laid. After the ovum is released into the oviduct there is a 3 minute window for fertilization. After which the ovum passes furthur down the system where the abulum (sp?) is developed around it. This is not really a varient yet. After that it passes into the area of the body where the shell is developed. That is where it spends about 23 hours. This can vary because it depends on protein, calcium, wellness of the bird, etc to form the shell. And as some of us have experienced it doesnt form at all sometimes. I would think light would effect it just because of the sleep cycle. Then again I am not a scientist

 

[aart]

Not a scientist here but my understanding is that a hen ovulates within 2 hours after an egg is laid. After the ovum is released into the oviduct there is a 3 minute window for fertilization. After which the ovum passes furthur down the system where the abulum (sp?) is developed around it. This is not really a varient yet. After that it passes into the area of the body where the shell is developed. That is where it spends about 23 hours. This can vary because it depends on protein, calcium, wellness of the bird, etc to form the shell. And as some of us have experienced it doesnt form at all sometimes. I would think light would effect it just because of the sleep cycle. Then again I am not a scientist

That part is pretty well known and documented.
It's what triggers the release of ova that @Shadrach is questioning, I think(but who knows<shrugs>.

 

[birdhelper84]

well scientist now saying the chicken came before the egg.which is what i have been saying since i was 5 years old "you need a mom chicken and a dad chicken of make baby chickens" my 5 year old self was ahead of the times lol.

 

[Ninjasquirrel]

That part is pretty well known and documented.
It's what triggers the release of ova that @Shadrach is questioning, I think(but who knows<shrugs>.

The answer to that would be the same as what triggers us to ovulate: the release of estrogen. So I think the better question is how estrogen release is affected by outside sources. Vitamin D and B12 can greatly affect estrogen release which would explain why light might effect it

 

[Ninjasquirrel]

well scientist now saying the chicken came before the egg.which is what i have been saying since i was 5 years old "you need a mom chicken and a dad chicken of make baby chickens" my 5 year old self was ahead of the times lol.

The simplest answer is usually the best

 

[aart]

The answer to that would be the same as what triggers us to ovulate: the release of estrogen hormones

Yes, but if you read the OP...the theory @Shadrach is questioning is about light exposure triggering the release of the hormones.

 

[Ninjasquirrel]

"Light plays a crucial role in vision and the release of various hormones; it also increases the efficacy of important factors related to the reproduction and behavior of poultry [5]. Moreover, light activates the development of reactive substances in embryos, such as vitamins and enzymes [6]. The patterns of light energy that reach the hypothalamic region of the brain, either via the optic nerve or directly through the skull and tissues, control the secretion of gonadotropin receptor hormone (GnRH), which stimulates the pituitary gland to release gonadotropins: luteinizing hormone (LH) and follicle stimulating hormone (FSH). The amount of gonadotropins and the timing of their release influence the rate of sexual maturation and the ovulatory cycle [7]."
-S. C. Chang, M. J. Lin, Y. K. Fan, T. T. Lee, Effects of lighting intensity on growth and reproductive performance of breeder geese, The Journal of Applied Poultry Research, Volume 25, Issue 3, September, 2016, Pages 315–321,
This is an excerpt from the journal of Applied Poultry Research. For further reading:
https://academic.oup.com/japr/article/25/3/315/2363656

Hopefully this helps our OP