Quick, picture a scientist. You pictured somebody in a lab coat, looking at a test tube didn't you. Nobody ever pictures a group of people gathered around and mounting a turkey's head on a spike in order to see whether another turkey will attempt to have sex with it, but sometimes that's what science involves and quite frankly you need to adjust your stereotypes.
In the 1960s, Dr. Martin Schein and Dr. Edward Hale designed a notoriously grim experiment about the sex lives of turkeys. They had already found in previous experiments that male turkeys would basically have sex with anything going. When male turkeys find female turkeys in their pen, they will attempt to have sex with them. When male turkeys find humans in their pens, they will attempt to have sex with them. If they have been exposed to humans during the imprinting phase shortly after hatching, and are later confronted with humans and females at the same time, they will treat the event like an interspecies version of Eyes Wide Shut.
"When confronted with both sexually receptive female turkey and humans simultaneously in the test pen," the team wrote. "Those males that had been imprinted to turkeys the year before devoted exclusive attention to the female turkeys while those that had been human-imprinted were equally devoted to the humans."
While a bit icky, all of the participants were at least not dead.
In a subsequent experiment where the same could not be said, the scientists investigated what exactly it was that got a turkey going. This was done by creating a taxidermy turkey and placing it in the pen with the male turkeys. The turkeys were unbothered by the fact that the turkeys showed no signs of life, and performed necrophilia on the stuffed animals without hesitation.
Next, the scientists removed body parts from the turkeys to see if that had any effect on the male turkeys' mating attempts. They took off the feet to no effect, the wings to no effect, which is to say the male turkeys still considered the dead bird a mating opportunity, and mounted it.
The scientists kept going until only a head on a stick remained, like the world's most disgusting popsicle. The male turkeys still attempted to have sex with it.
“Male turkeys presented a body without the head displayed but did not mount," the team wrote, according to Atlas Obscura. "Presenting the head alone (upright) released display behavior followed by ‘mounting’ and copulatory movements immediately posterior to the head.”
The team believed this was because the back of the female turkey's head would be the only thing visible to males anyway during mating. Apparently, they were unbothered by seeing that the neck was attached to nothing beforehand.
The experiment was repeated in chickens, who were not fussed about a head. They would have sex with a headless body of a hen, but not a disembodied head. Which in terms of poultry, it turns out is apparently quite discerning and fussy.