In the not too-distant future of the stories that Matty and I are working on, a pair of cockatrice characters will be introduced. I'd like to take this opportunity to nail a few things down about the creatures.
The most obvious fact about cockatrices is that they did not arise naturally, but were designed by biomancers1 in the past. A cockatrice bloodline begins when a biomancer alters a rooster to make it partially female. The altered rooster, through self-fertilization, will lay brown leathery-shelled eggs that will hatch after forty-eight days of incubation.
Contrary to popular belief, cockatrices do not turn the victims of their gaze into stone. Instead, the magical attack instantiated by their gaze causes all of the calcium in the victim's blood and skeletal muscles to be pulled out to the skin. The calcification of the skin causes the appearance of a stony metamorphosis.