The four children had eaten chicken which had been slaughtered while showing signs of disease, say doctors in the south-eastern city of Van.
The hospital's head doctor confirmed the death of the 14-year-old boy to the semi-official news agency Anatolia. Test results could be known on Monday, said a health official. Bird flu is only one possible cause, doctors say.
"They are suspected cases of bird flu since they ate a sick chicken and they were in close contact with fowl," the hospital's head doctor said.
One other boy and two girls remain in hospital. Two other patients, including another child, were also reportedly sent to the hospital for tests. Turkey has had outbreaks of the H5N1 strain in birds, but no human cases.
The H5N1 strain of bird flu has killed more than 70 people in Asia since 2003. Millions of birds have been slaughtered as authorities across Asia fight to contain the disease.
It is feared the virus could mutate into a form which spreads from person to person, a development which experts say would result in a global flu pandemic leaving millions dead.Last Mod: 20 Eylül 2018, 18:16