1626, April 9 (to present?): Francis Bacon’s Fowl Ghost
Francis Bacon, famous English philosopher and statesman [1561-1626], died of pneumonia on April 9, 1626... and though I know of no reports of his ghost returning, it's been told that he may have caused a most unusual haunting to occur at Pond Square, in London, England, as a direct circumstance of the same exposure to the cold that many believed killed him a few days after.
Bacon was traveling by coach through Highgate, London, with a companion, Dr. Witherborne (who was physician to the King of England, no less), to "take the air" one chilly day, he was looking at the snow on the ground when a thought occurred to him: could snow preserve flesh as well as salt? He briefly discussed this idea with Witherborne, whereupon both agreed to test the thought immediately. The coach was stopped, and the two men bought a hen from a woman at Highgate Hill, had her gut the animal, then they stuffed internal cavity with snow... Bacon did this himself, we're told.
The results of the experiment were soon forgotten, however, as Bacon shortly thereafter showed signs of great illness, sudden and worrying enough that instead of returning to his lodgings, he went to the house of the Earl of Arundel which was in Highgate, and given a bed there. No one suspected how ill Bacon really was, including the man himself; in the next day he penned a letter in wobbly handwriting thanking the Earl (who was out of town during Bacon's stay) for allowing him to convalesce in Highgate... and a day or two later, Bacon died.
Since that time, a spectre has been reported as occasionally appearing at Pond Square in Highgate, the approximate location of Bacon's fatal experiment... but it's not the ghost of Francis Bacon that's reported; after all, he's not the one who died at Pond Square. What's been reported is the ghost of the chicken he stuffed!
Four distinct sightings of the featherless ghost have been reported. The first two known sightings took place during World War II.
During that time, Mrs. John Greenhill had often seen the spectre on moonlit nights, and described it as "a big, whitish bird." Featherless, the ghostly bird half-ran and half-flapped in circles until it disappeared.
Also during the war, Aircraftsman Terence Long was crossing Pond Square one night when he heard the sound of hooves and carriage wheels... but when he looked around, all he saw was shivering, half-plucked chicken running in circles. An Air Raid Precautions man informed Long that the strange bird was a long-time resident of the area, and that another man had tried to snare it a month or two earlier, but the bird had disappeared into a brick wall.
One night in January, 1969, the bird was spotted near a wall by a motorist who was having car trouble. Suspecting the featherless chicken had been abused by local youth, he looked a around to see if anyone was near before walking over to help it... but the bird was gone by the time he looked back.
It was spotted again, in February 1970, as a young man and woman were saying goodnight to each other. Noiselessly, the white naked bird landed on the ground beside them, ran in a circle twice, then vanished into the dark.
Perhaps other sightings have occurred, but the witnesses are too embarrassed by the odd situation to tell anyone! Then again...
My Source's Source
As far as the story of Bacon catching pneumonia while stuffing a chicken with snow, this is a known and roughly accepted story regarding the great man's death, published as early on as 1680 from the notes of someone who had a reasonable chance of being in the know on the matter. Some argue that the snow experiment didn't give Bacon the pneumonia, others state he died from a different disease... but the fact Bacon died after attempting this experiment doesn't get argued with. Of course, we're here more because of the reports of the phantom fowl, now aren't we?
At the moment I have only one source for the ghostly chicken story, Reader's Digest Mysteries of the Unexplained... which is strange, since Francis Bacon was famous enough that I expected to find something else on this matter. The book above gives as it's source Peter Underwood's Haunted London, which I have yet to get a copy of. Hopefully, this second source will point to where it got the story, if it wasn't invented by the author. And, considering that I can find no other information, the idea that Underwood invented the tale is a real possibility if nothing else turns up!