Chicken Vet on supplemental light to increase winter egg production

[LynnTXchickenmom]

I found this post with a message from a chicken-focused veterinarian very helpful. In it, he explains exactly how light stimulates egg production (not through eyesight, but rather a gland on the forehead)) and debunks two theories I have seen here and elsewhere: 1) Giving chickens supplemental light in the winter does not decrease lifespan, and 2) it doesn’t make them run out of eggs faster—chickens have many times more ova than years in a natural lifespan to lay them all.

https://the-chicken-chick.com/supplemental-light-in-coop-why-how/

We have 18 pullets who started coming into lay around Christmas. Two weeks ago, we were getting 14-17 eggs per day. When the pullets were laying well, we were having a bright, sunny, warm spell with highs in the 70s. Then we had cloud cover and rain, and this week cloud cover and an ice storm—a Texas blue norther. Once the days became darker, egg production fell to 6-7 eggs/day. As we started this project to save the $5/doz grocery store price for reg cage eggs and to sell fresh, free range eggs to a friend who prefers them, we need to recoup our initial start up costs and at least break even this year. So given the advice of this vet, we will add supplemental light 20 min before dawn each morning and keep increasing it steadily until the light + day length = 14 hours. When the season provides 14 hours for us naturally, we will turn it off. I am expecting fewer eggs when we suffer extreme heat this summer (over 100 deg, which can be several weeks) and have plans for adding a shade sail on the south side of our coop (the rest of the coop and run is shaded by trees) and possibly a mister. Our flock is all Rhode Island Reds and we need them to produce an avg of 300 eggs per year per chicken, as this breed is capable of doing.

For the light, we are running an outdoor extension cord to the coop from a garage receptacle. The timer will be in the garage—a $10 mechanical one. We will hang the end of the cord from a hook in our coop rafter and plug a $3 plug-in light socket into it with a light bulb, out of the birds’ way. Least expensive option that I could find for a coop light.

 

[saysfaa]

Wow, that article is great!

My facorite parts were that the length of dark is what matters rather than the length of light. And that fluorescent lights are inadvisable because of how chickens eyes function.

The studies using genetically retina-less chickens are interesting too. In people, different kinds of vision are processed by different neural pathways - some totally blind people will walk around chairs they can't see and didn't know were there. It is because their eyes are healthy, the disfunction is in the nerves between their eyes and the part of their brain that registers light and objects and such. But not between their eyes and the part of the brain that controls their movements.

In people, the circadian rhythm is dependent on function of eyes and neural pathways between the eyes and the HPA. It makes sense that chickens could be different. People have thicker skull and more frontal cortex, if nothing else.

Edit the grammar so it is people with thicker skulls and frontal cortex, lol, because otherwise it would bug me.

 

[Ridgerunner]

I've read that before, it is a good read. I will point out some things about day (or night) length. I can't copy and paste as that article is protected so I'll paraphrase. If you look at his first paragraph (his, not hers) he says it is the days getting longer that starts the hen laying and days getting shorter that stops her from laying. He does not say it is day length, it is the change in day length (or actually night length).

At various places further down he says it takes 13, 14, or 15 hours of daylight for hens to lay. Pretty inconsistent. It's a good thing that it doesn't take 14 or 15 hours of daylight because anyone living south of Houston, Texas on this side of the equator would never get any eggs, except maybe right at the summer solstice. In Houston at the summer solstice, the longest day of the year, daylight is barely 14 hours long. The rest of the year the days are shorter. If they needed 14 or 15 hours of daylight you'd have to keep the lights on all year. No one without lights would get an egg.

Even if the shortest amount of daylight they needed to lay eggs were 13 hours (it isn't), there would only be a few days a year south of Houston where chickens would lay without the lights being extended. I do not believe you have to have 13, 14, or 15 hours of daylight for hens to lay. I've had them lay quite well on my shortest days of the year, which were 10 hours long.

He mentions that they need to molt every 12 to 18 months to maintain health. I think that is important to know, some people get the idea that you can keep them laying forever by manipulating the lights.

The only thing I disagree with Dr. Mike Petrik about is that they need these extremely long days to lay. My experience says that is not correct.

 

[saysfaa]

... The only thing I disagree with Dr. Mike Petrik about is that they need these extremely long days to lay. My experience says that is not correct.

That, and "no evidence" lighting decreases longevity (given diet and such) isn't the same thing as evidence that it doesn't.

 

[Ridgerunner]

That, and "no evidence" lighting decreases longevity (given diet and such) isn't the same thing as evidence that it doesn't.

I don't disagree with what he said. If he has seen no evidence then he has seen no evidence. That's pretty straightforward. Do you have evidence to the contrary?

 

[saysfaa]

No, I don't. I'm not interested enough to look for any either; I don't have electricity in my coop for other reasons. I thought it was presented as known to not be a factor. I can see it could be read either way.

I lean toward thinking he is right- at least if it isn't taken to extremes, that is they get enough sleep. I don't know how much is enough for chickens.

 

[aart]

I lean toward thinking he is right- at least if it isn't taken to extremes, that is they get enough sleep. I don't know how much is enough for chickens.

That and the fact that if they lay non-stop all year long, without a break to molt and 'rest', their overall health may suffer.

 

[Ridgerunner]

I thought it was presented as known to not be a factor. I can see it could be read either way.

You may have heard the phrase "you can't prove a negative." You can test something every way you can possibly think of and if it doesn't cause any harm, you may be OK with it. But that doesn't mean somebody can't come up with a test where it fails sometime in the future.

That's the way the scientific method works. Somebody comes up with a theory. If there is enough interest others test it to see if the results are repeatable. Others do everything they can to find a place it doesn't work. That's why the theory of gravity is still a theory. They've discovered a lot of other forces and particles while testing gravity so gravity is better defined but no one has shown it to be wrong so they use it as a law until somebody comes up with something better.

Something like my theory that if a broody hen stays on the nest for two consecutive nights you can give her hatching eggs. It's always worked for me so I'll keep using it. It is always possible it will not work the next time, I can't say it will work every time. Even if it does fail I'd probably keep using it because it has worked so often.

I lean toward thinking he is right- at least if it isn't taken to extremes, that is they get enough sleep. I don't know how much is enough for chickens.

I don't know how much dark time they need either. I have nothing to base it on. I don't extend lights and do nothing to interfere with them molting when they want to.

 

[saysfaa]

I agree. But he is talking evidence, not proof. We can't prove gravity but there is a LOT of evidence for it.

 

[LynnTXchickenmom]

I've read that before, it is a good read. I will point out some things about day (or night) length. I can't copy and paste as that article is protected so I'll paraphrase. If you look at his first paragraph (his, not hers) he says it is the days getting longer that starts the hen laying and days getting shorter that stops her from laying. He does not say it is day length, it is the change in day length (or actually night length).

At various places further down he says it takes 13, 14, or 15 hours of daylight for hens to lay. Pretty inconsistent. It's a good thing that it doesn't take 14 or 15 hours of daylight because anyone living south of Houston, Texas on this side of the equator would never get any eggs, except maybe right at the summer solstice. In Houston at the summer solstice, the longest day of the year, daylight is barely 14 hours long. The rest of the year the days are shorter. If they needed 14 or 15 hours of daylight you'd have to keep the lights on all year. No one without lights would get an egg.

Even if the shortest amount of daylight they needed to lay eggs were 13 hours (it isn't), there would only be a few days a year south of Houston where chickens would lay without the lights being extended. I do not believe you have to have 13, 14, or 15 hours of daylight for hens to lay. I've had them lay quite well on my shortest days of the year, which were 10 hours long.

He mentions that they need to molt every 12 to 18 months to maintain health. I think that is important to know, some people get the idea that you can keep them laying forever by manipulating the lights.

The only thing I disagree with Dr. Mike Petrik about is that they need these extremely long days to lay. My experience says that is not correct.

Great point. I live in TX and sincerely hope the 12 hrs of daylight we get in late Marchwillbe enough.