Jack Nicholson was thinking about very special chickens - specifically those deadly flying hens, reeking with venom: the kind that will bury their beaks in your belly as you sleep, the ones that cackle in dark closets and lurk like vultures just beyond the transom. More properly, Jack Nicholson was thinking about people who are obsessively concerned with such chickens. "People who see chickens," he concluded, "don't belong in places like this."

It was just before Christmas of 1974 and Nicholson was in his second week of researching his role of Randle Patrick McMurphy for the upcoming filming of Ken Kesey's classic One Flew over the Cukoo's Nest. It was 6:00 a.m. - an hour to go until dawn - and Nicholson, a nurse, a doctor and a technician were tiptoeing down a long drab hallway on the third floor of the Oregon State Hospital. The technician was pushing a small machine which rolled silently on four rubber wheels. A long electric cord was coiled on top of the machine.

Every few feet there was another barred door and, above, a heavily wired transom. The four were as quiet as possible. Behind the doors slept the most certifiable deranged individuals in the state. No reason to wake them unnecessarily, perhaps stir them to anger at the sight of the machine.

Nicholson considered himself a reasonably conversant parlor psychiatrist. He had read Frances Farmer's Will There Really Be a Morning, a horrifying account of one actress's battle with insanity, never dreaming that he would one day play the lead in the movie version of that book, never dreaming he would see what he was queasily about to see.

Prior to his research in Oregon, Nicholson had been convinced that the term "insanity" was archaic. He associated it with people who saw chickens. But the patients he met in the OSH wards seldom saw chickens and their behavior seemed to Nicholson no more loony than that of an average weekday shopper in Salem's Pay Less department store. The problem was that a few of these people had been involved in crimes of extreme violence and cruelty. One friendly fellow had inflicted 20 stab wounds on a person he had never met before. A gentle, dignified, older man had committed rape twice, and the rapes involved mutilation and maiming. One spindly, prematurely gray man discussed bombs in the same leering, lustful tone that another man might use to describe a sexual conquest.

This last broke Nicholson. He was living in a rented house in Salem, getting up before dawn every morning and plodding off to the hospital in a dank fog. After 12 to 14 hours of talking with patients and doctors and aides, he plodded back home in what seemed to him to be arctic desolation. Winter in Salem, Oregon, can add several hundred pounds of bad psychic baggage to the soul of a Southern Californian like Jack Nicholson. There is a constant chill fog and the sun, at high noon, could possibly be that faint glimmer behind the brightest cloud bank. It is like living inside an Edger Allan Poe poem, minus 20 degrees centigrade.

Further, something about Salem failed to lend itself to after-dark socializing. By state law, all Oregon institutions must be located in Marion County - which in practice means Salem, which is also the state capital. The town is overladen with cons and ex-cons, with social workers and therapists and hardship cases, with psychiatrists and mental patients and ex-mental patients and politicians. The cliche, of course, is that it is impossible to tell one from the other.

There are a number of bars in Salem but Nicholson is not much of a drinker. He imagines that he is amusing after four or five stiff ones. After that, he says, he is likely to wake up in his garage with half his entrails on his chest, the taste of soiled sweat socks in his mouth and two tiny men playing bass drums just behind either eyeball. Nicholson much prefers to light up, mellow back and listen to music. Compatible company - of either sex - for Nicholson, was not to be found.