Sexing eggs!

[BillJ]

I'll put off starting the incubation for a few extra days. The granulated soy lecithin likely will have an effect on egg passage through the hen which may then be more rounded.

Back in the early to mid-1980's when a subscription to the journal SCIENCE was affordable, there was a research article on the effects of a daily 3 tablespoon dose on primate alcoholic fatty liver disease. Two groups of primates, one fed a diet mostly comprised of calories from alcohol and another with the same diet but with granulated soybean lecithin daily. A couple of years and the animals had liver biopsies. Stark difference, distorted fatty liver cells versus normal liver cells.

So in fatty liver disease the fat becomes built up in the liver while in a healthy liver I think it's fed over to the gall bladder and used in the production of digestive enzymes. With the fat more bio-actively available there should be an effect on egg passage.

This may be an early indication of round versus pointed egg gender tendencies. Someone with pure sex-linked birds would be able to tell much more quickly than I of course.

BillJ

 

[redsix]

I'm thinking the egg shape has more to do with flock conditions, hen activity, than roo sperm chromosome composition, e.g X or Y. I have a single laying hen, a older black copper maran, among four younger old rhode island reds.

First egg I put aside for hatching is the roundest, ratio 1.433. She was normally free ranging with the old man and other hens. After the first saved egg I started dropping her in for a short period with a much younger roo, this when it was convenient to catch her. Following those days the eggs tended to be more pointed, i.e. 1.495, 1.496, 1.513.

Earlier post posited dropping the incubator 2° tended toward hens, citing a great hen to roo ratio that resulted. I recall in biology class that red blood cells have the optimal surface area for carrying oxygen and a true globe the worst. Since pointed eggs have more surface area they'd tend to heat better, faster but conversely lose heat quicker too. So shape does have an effect though indeterminate. Perhaps the shape describes an effect on oxygen availability to the embryo.


Also I'm wondering about egg storage conditions. I opted for one of those new clear plastic egg cartons but I've started to wonder about fertile egg oxygen consumption and have gone to an open cardboard carton while waiting for enough to start incubation. I thought of this because I've been snugging up my homebrew incubator and wonder how a higher incubator oxygen content would effect development. While serving aboard an antique submarine circa 1944, we were held down by sonar in war games for an extended period searching for a thermal. We started releasing O2 into the atmosphere from tanks but had the option to spread lithium hydroxide crystals to absorb CO2. Improved now, submarines carry lithium hydroxide curtains so as not to release caustic dust. The USN gets the curtains for $19 each. These also produce heat. So, small patch versions of these shouldn't be expensive and might be a nice addition to an incubator. But if pointed eggs produce more roo's due to increased oxygen availability to the embryo then putting a lithium hydroxide patch in an incubator would get more roo's fewer hens.

Bill J

I don't think a carton is a very good thing to put eggs in that you are going to incubate. I think it is better to leave them lying horizontal and turn them often.

 

[BillJ]

I don't think a carton is a very good thing to put eggs in that you are going to incubate. I think it is better to leave them lying horizontal and turn them often.

Thanks. I'll make the change to horizontal and turn them not infrequently.

 

[junebuggena]

Thanks. I'll make the change to horizontal and turn them not infrequently.

Keeping them in a carton is fine, as long as they are kept fat-end-up. That's how all my eggs get stored. Then, when I need to hatch some chicks or get a broody hen, all I have to do is grab the freshest carton and pop the eggs in/under to incubate.

 

[BillJ]

That's exactly what I thought. My concern was that using a plastic carton might have been a mistake tho eggs don't breath much this early. Then I thought, maybe he's right, considering the reason might be a cardboard carton might suck moisture out while storing.

 

[BillJ]

To recap, only one laying hen, best bird historically (named Little Blackie), three RIR hens of which one does lay rarely but softish shell and poorly shaped. The old man roo, a BFCM, and hens were segregated from the other mostly younger roo's and free ranging. First saved egg from Little Blackie had a height/width ratio of 1.43. I started putting Little Blackie in with a young roo some days. The ratio changed to a range of 1.44 to 1.51. I attribute this as possibly due to increased physical stress/exercise from the young roo contact. Average egg weight dropped just a little.

I would be starting the incubation tomorrow but decided to test my theory that lacing the hen's water with soybean lecithin granules will increase the probability of eggs becoming female. I added the soybean lecithin to their water yesterday. It's been warm so they've been drinking. No egg yesterday as I screwed up two nights ago and left the light on in their roost all night. There's an egg out there now. Two more and I'll hatch the last three and the eggs less the heaviest and from the remainder picking those with a ratio closer to 1 than the others.

Since Little Blackie will be laying the three weeks during incubation, I'll keep a record of weight and ratio to see if the soybean lecithin granules lacing their water has generally effected their shape.

I see online a complaint that soy fed chickens have eggs with increased estrogen levels and may be contributing to pre-mature sexual development in young girls. I note if this egg gender influencing technique is effective, one might only feed one's hens water laced with soybean lecithin granules in a period approaching and during egg harvest for hatching and back to a regular diet otherwise.

BillJ

 

[BillJ]

The gender of an egg is already determined by the time it's laid. All that the dipping might do is to prevent one gender or another from developing and hatching properly... It's not going to magically change the genetic material already inside the egg.

I sometimes watch one of the birds running and think how much the running bird reminds me of a dinosaur. I think the closest living thing to dinosaur is a crocodile. (The archosaur, or so-called "ruling reptile," roamed Earth about 250 million years ago, and "was something that was very reptilian, very early-dinosaur-ish, and then it evolved into modern-day crocodiles and birds," from http://www.latimes.com/science/sciencenow/la-sci-sn-crocodile-bird-genome-20141212-story.html)

So, with crocodiles, sex is determined while the egg is in the nest. Colder gets females, mid-temp (3°C range) produce males, and above that gets females again. I wonder if the temperature effect is from genes that are conserved in nature, common to chickens as well as crocodiles.

Colder incubation begetting females seems plausible.

So, cooler incubation would mean slower moisture loss. Makes me wonder if dry incubation would tend to lower the female numbers. And that also makes me recall that a perfect globe has the least surface area. Rounder eggs would have less surface area to lose moisture and pointed eggs would lose moisture quicker.

 

[junebuggena]

I sometimes watch one of the birds running and think how much the running bird reminds me of a dinosaur. I think the closest living thing to dinosaur is a crocodile. (The archosaur, or so-called "ruling reptile," roamed Earth about 250 million years ago, and "was something that was very reptilian, very early-dinosaur-ish, and then it evolved into modern-day crocodiles and birds," from http://www.latimes.com/science/sciencenow/la-sci-sn-crocodile-bird-genome-20141212-story.html)

So, with crocodiles, sex is determined while the egg is in the nest. Colder gets females, mid-temp (3°C range) produce males, and above that gets females again. I wonder if the temperature effect is from genes that are conserved in nature, common to chickens as well as crocodiles.

Colder incubation begetting females seems plausible.

So, cooler incubation would mean slower moisture loss. Makes me wonder if dry incubation would tend to lower the female numbers. And that also makes me recall that a perfect globe has the least surface area. Rounder eggs would have less surface area to lose moisture and pointed eggs would lose moisture quicker.

Reptile gender can be influenced by temperature, but that does not hold for birds. There has been a lot of research done on incubating chickens, if it was as simple as altering the incubation temp the hatcheries wouldn't have so many cockerels to dispose of. Lots of people on this site dry incubate, but it doesn't change the outcome for gender.
Oh, and the closest living relative to the Tyrannosaurus Rex is the group of birds that chickens and ostriches are a part of. Crocodilians actually predate dinosaurs, and are a completely different species.

 

[Lozuufy]

The kind of bird that LOOKS most like a dinosaur (to me) is the hoatzin though...

https://s-media-cache-ak0.pinimg.com/736x/19/9a/1b/199a1b7b8019c580a683e6aff85eb901.jpg

 

[BillJ]

Reptile gender can be influenced by temperature, but that does not hold for birds. There has been a lot of research done on incubating chickens, if it was as simple as altering the incubation temp the hatcheries wouldn't have so many cockerels to dispose of. Lots of people on this site dry incubate, but it doesn't change the outcome for gender.
Oh, and the closest living relative to the Tyrannosaurus Rex is the group of birds that chickens and ostriches are a part of. Crocodilians actually predate dinosaurs, and are a completely different species.

I see this 2011 article supports your view that egg sex is determined before laying. Still, I wonder if this is absolute. http://www.ncbi.nlm.nih.gov/pubmed/21479544

Egg sex can be determined by estrogen concentration. http://www.ncbi.nlm.nih.gov/pubmed/20081077

And yes, once gender is established in the egg it's unlikely to change but is reversible in ovo. This would suggest that granulated soybean lecithin supplementation to hen feed would feminize some ZZ males. http://www.ncbi.nlm.nih.gov/pubmed/22539680

This article says that higher estrogen levels makes for more sexing errors due to chicken external sexual dimorphism near the time of hatch. http://www.ncbi.nlm.nih.gov/pubmed/1437983 So, lecithin to feed might make for sexing errors without actually increasing the number of hens.

This abstract shows estradiol and progesterone drop before an egg laying pause and increase before egg laying restart. http://www.ncbi.nlm.nih.gov/pubmed/11987470 Interestingly, the addition of granulated soybean lecithin to the water caused one of the RIRs shift into laying mode and passed a soft egg.

So, yes. Incubation temperature as a sex determining factor seems improbable. But, hen estrogen levels from granulated soybean lecithin supplementation is more likely to sway sex toward females. But then again, supplementation with exogenic plant estrogen might have an effect on the bird's own estrogen production and gene expression. If it causes a fall in the bird's natural estrogen production it may possibly (conjecture), after some weeks, cause a shift to a broody state. http://www.ncbi.nlm.nih.gov/pubmed/7819456

And round versus pointed egg sexing, another abstract, which I can't locate now, shows increased estrogen levels will slow early embryo development. This might argue for estrogen levels influencing egg form factor - rounded versus pointed.

BillJ