No. It happens with snakes, amphibians (eg turtles) and some frogs/toads that sex is determined by temperature, but not chickens. Mammal DNA is sexed at conception/fertilisation, I don't know of a single mammal that isn't.
I have read of only 2 studies that claim you can influence the hen to roo ratios of your hatching eggs. And then only marginally.
The first method shown to effect the more hens to roos had to do with the age of the breeding roo. The study suggested that young breeding males tend to produce more pullets than roos. I dont know that I believe it though since all of my roos are one year or less of age and I seem to be covered up in roo chicks.
The other method involves feed. The study suggests that free feeding sorghum grain, (I assume they are refering to Milo), in addition to the regular laying feed, to laying hens will effect the gender of the chicks. Results generally dont show up for a month or two after starting to feed the sorghum, but hen to roo ratios tended to raise to about 60/40 pullets to roos. I havent tested this and the study wasnt a longterm study, so take it as just something that might or might not work.
Now for the wives tales. I havent tried this either, but my cousion and my uncle swear that you can select the gender of the eggs you are incubating by suspending a needle on a string above the egg. If the needle swings back and forth, the egg will produce a roo, if the needle swings in a circle or arch, then the egg will produce a pullet. My uncle also swears he can guess the age of any woman by suspending a ring on a string above her head. He claims it will rotate one turn for every year of age. My wife wont stand still long enough for me to test this theory on her.
Quote:I've heard of this too. I hatched a few batches of sex-link chicks this year (BO roo on BR hens), and found it to be true (though please realize that I had a relatively small sample set). When I had my still-air bator @ 100F, I got 50/50 pullets to roos. When I had it @ 102F, I got 90/10 pullets to roos. I didn't have the heart to break open all of the eggs that hadn't hatched to see if they were pullets or roos. I'm really wishin' I had checked them now!