In 2015, the National Institutes of Health decided to retire all the chimpanzees it owned. Since then, animal welfare groups have been pushing for quicker action, even as some of the facilities that once conducted experiments have urged caution, arguing that some chimps are too old and sick to be moved.

On Thursday the N.I.H. announced that an independent panel of veterinarians had determined that the 44 chimpanzees remaining at the Alamogordo Primate Facility, or A.P.F., in New Mexico were too ill to move, as the facility had contended.

In a statement, Dr. Francis S. Collins , the director of the N.I.H., said that the “N.I.H. expects that these 44 chimpanzees will live out the remainder of their lives at A.P.F. to ensure their safety and welfare.”

Rana Smith , the president of Chimp Haven, expressed disappointment at the decision. “We respect the medical opinions of the veterinary panel,” she wrote in an email. However, she said, “we firmly believe that sanctuary life is the best place for chimpanzees.”