is in a
hospital for treatment of a recurring bout of double pneumonia.
A statement from his publicist on Tuesday said Haggard has had to postpone his concert dates in March.
The 78-year-old singer had also cancelled some dates in February because he was still feeling weak from a previous case of pneumonia in both lungs, but then returned to the stage last month.
The statement said that his doctors wanted him to take one more month off the road to rest and recover.