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I was watching discovery channel tonight. An episode about an aligator farm..........Anyway they said they could predetermine the sex of the hatchlings by the level of humidity. For example if they wanted to produce more males they would raise the humidty. To produce more females they would lower the humidity levels on the eggs they were incubating.

Just curious is it possible to control the sex of chicks prior to hatching?

I know a lot of budgie people swear by full spectrum lighting. I have a friend who one year produced 1 hen out of 60 chicks she bred. Kind of hard to keep an exhibition breeding program going producing so few hens. She put in full spectrum lighting in her bird room for the next year and she got 60% hens. The key one has to remember is to keep the bulbs wiped down from dust or they don’t do the job needed. She also got her light bulbs in the plant department of Home Depot. The are the same thing, less expensive and under different packaging than the full spectrum lighting sold at many parrot shops.

1. The think that the lower temperature for producing male alligators is 87 degrees F, and the higher temperature for females is about 93 degrees. This is way below the necessary brooding temperature for birds, although my first family of frizzle chickens eggs would hatch when left by the refrigerator motor, about about 90 degrees...they were so easy to hatch, that I used them to compare results in my incubator when I set the rarer eggs.
2. Sex determination in birds might be more sex-chromosome-related, with a double-inheritance (that is, from both parents) resulting in males.
Bird sex chromosomes are listed as WZ, with ZZ=male, I think.
This is the opposite of mammals, which have XX= female and XY=male.
3. When we raised dairy goats, the kids conceived in summer were mostly males, and the kids conceived in fall were close to even. Because we controlled the matings, those conceived towards the end of the heat period were a slightly larger percent of female kids; matings at the beginning of the heat period resulted in up to 90% buck kids.

I read something about sex determination in zebra finches once. Something about if there was a mite infestation, the hen would lay the female eggs first and the male eggs last, because the female babies are hardier and could withstand the mites better. So the females would hatch first and hopefully the mite problem would be less by the time the males hatched. Something like that...

But reptiles are completely different than birds and mammals anyway. I wouldn't put much stock into trying to hatch certain sexes out in birds. The only thing that I've experienced that's come anywhere close to that is my greencheek pair that just had a clutch of five males. I think that must have been a coincidence though.

Alligators do not incubate their eggs with body heat. They build a biomass of composting materials and attend to it, but do not sit eggs as birds do. The mother arranges the composting material at intervals to control the temperature. I believe the sex difference may be related more to temperature, not humidity.

If you mess with humidity in incubating birds, alot of things can go wrong. Too high humidity outside the egg, and they do not loose enough moisture and pip below the air space and drown before hatching. Too dry, and they dehydrate and weaken, or can stick to the eggshell and not be able to rotate and complete scoring the eggshell to hatch.

I vaguely recall reading some theory that gender may be related to minute temperature differences, but I thought it was that more females were hatched at slightly higher temperature. Perhaps in the wild, when food is scarce, the hen is off the nest for longer periods in order to forage, and could be this has some bearing on what is the sex of the next generation. It is a liablity to be an egg laying female in times of food shortage.

To find out, you would have to test it, and that would be the hard part. What birdkeeper would want to use a control group for a scientific test? Meaning half of a large group of eggs was exposed to a higher temperature, and another half of identical eggs was exposed to lower, and compared to yet another group exposed to the normal medium temp, and no other variable conditions, then see what the result was. I have always wanted to give my birds the best care, and been unwilling to experiment. I think most feel the same way, and that is why we rely on so much anecdotal evidence.

tigerlily wrote: To find out, you would have to test it, and that would be the hard part. What birdkeeper would want to use a control group for a scientific test? Meaning half of a large group of eggs was exposed to a higher temperature, and another half of identical eggs was exposed to lower, and compared to yet another group exposed to the normal medium temp, and no other variable conditions, then see what the result was. I have always wanted to give my birds the best care, and been unwilling to experiment. I think most feel the same way, and that is why we rely on so much anecdotal evidence.

This would be a great idea for a science experiment for 13 yr old son. He raises chickens for 4H


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I BREED MOST TYPES OF REPTILE AND THEY LAY THERE EGGS IN SAND AND ITS THEN TRANSFERED INTO VERMICULITE AND PUT IN THE INCUBATOR AND YES YOU COULD GET MORE OF ONE SEX THEN ANOTHER BUT IN BIRDS ITS DIFFERENT THE MOTHER HEATS UP EGGS AND IF YOU MESS WITH THE HUMIDITY THEY MIGHT NOT HATCH AND YOU WILL LOSE MANY EGGS.

Believe it or not I have found it to be very close, but of course I just raise finches...also N.F.S.S. had a large dicussion about this subject.