On the first night after the decapitation Mike slept with his severed head under his wing.
Despite Olsen's botched handiwork, Mike was still able to balance on a perch and walk clumsily; he even attempted to preen and crow, although he could do neither. After the bird did not die, a surprised Mr. Olsen decided to continue to care permanently for Mike, feeding him a mixture of milk and water via an eyedropper; he was also fed small grains of corn. Mike occasionally choked on his own mucus, which the Olsen family would clear using a syringe.
When used to his new and unusual center of mass, Mike could easily get himself to the highest perches without falling. His crowing, though, was less impressive and consisted of a gurgling sound made in his throat, leaving him unable to crow at dawn. Mike also spent his time preening and attempting to peck for food with his neck.
Being headless did not keep Mike from putting on weight; at the time of his partial beheading he weighed two and a half pounds, but at the time of his death this had increased to nearly eight pounds.
Mike was on display to the public for an admission cost of 25 cents. At the height of his popularity the chicken earned princely $4,500 USD per month ($50,000 in 2005 dollars) and was valued at $10,000. Olsen's success resulted in a wave of copycat chicken beheadings, but no other chicken lived for more than a day or two. A pickled chicken head was also on display with Mike, but this was not Mike's original head, as a cat had already eaten it. Mike was later examined by the officers of several humane societies and was declared to have been free from any suffering.
A children's playground chant soon emerged:
Mike, Mike, where's your head? Even without it, you're not dead!
Post mortem, it was determined that the axe blade had missed the carotid artery and a clot had prevented Mike from bleeding to death. Although most of his head was severed, most of his brain stem and one ear was left on his body. Since basic functions (breathing, heart-rate, etc) as well as most of a chicken's reflex actions are controlled by the brain stem, Mike was able to remain quite healthy. Other sources, including the Guinness Book of World Records, say that the chicken's severed esophagus passage could not take in enough air properly to be able to breathe; and therefore choked to death in the motel. However, breathing occurs through the trachea, not the esophagus.