By James Gorman

New York Times News Service

Faylene is a 35-year-old chimpanzee now housed at the Alamogordo Primate Facility in New Mexico.

She is owned by the National Institutes of Health, along with 50 or so other chimpanzees there, most of whom have been used in biomedical research.

The NIH decided in 2015 that all federally-owned or supported chimps would be transported to sanctuaries, which would seem to make pretty clear the future of about 270 chimps (as of March) it still owns or supports outside sanctuaries.

But nothing has been simple since the government first started seriously questioning the value of research in chimps in 2011. Gradually, in a series of steps, they first banned new biomedical research and then stopped all biomedical research on all NIH chimps in 2015. That same year the U.S. Fish and Wildlife Service declared all chimps, even those in captivity, endangered, effectively banning all invasive research on all chimps, whoever owns them.

Numbers change as chimps move to sanctuaries and die. But the NIH census as of Jan. 1 counted 130 federally owned chimpanzees still housed at the Michael E. Keeling Center for Comparative Medicine and Research in Bastrop, Texas, and 79 federally supported chimpanzees remaining at the Southwest National Primate Research Center in San Antonio. It counted 79 at Alamogordo, but at least 23 of those have since moved to a sanctuary.

The latest twist in the seven-­year saga of changing the federal approach to chimpanzees in research is the question of whether chimps in ill health should be moved at all, or stay where they are, retiring in place.

Earlier this month, the NIH Council of Councils, a title that deserves some sort of award for cryptic naming, approved a working group report on the question.

James Anderson, the NIH director for program coordination, planning, and strategic initiatives, said the working group was established in the first place because of the need for a common framework to deal with moving old and ailing chimps. Each lab or facility had its own method for assessing chimp health, but the report sets out common criteria.

The problem the NIH faces, he said, is, “OK, we’re going to move all these chimps. But we don’t want to kill them” in the process. The chimps suffer from age-related diseases like diabetes and heart problems and from the effects of the experiments they were part of, infection with viruses, for example, although the lasting effects of those infections is hard to pin down. About 7.5 percent of the chimpanzees owned and supported by NIH die each year, he said.

The report urges, once again, that all chimps should be transferred to sanctuaries, unless such a move is “extremely likely” to shorten their lives. The council forwarded the report to the director of the NIH. There will be a 60-day public comment period and Francis Collins, director of the NIH, will likely make a final decision on the recommendations in September.

This news might seem to be no news at all, in the sense that the movement of chimps to sanctuaries will continue along as it has been, with, it would seem, rare exceptions.

But there are details to be worked out, and the fact that the working group was established at all indicates a deep difference in opinion about what a good end of life is for captive chimpanzees.

Simply put, one side thinks that many chimps may be better off where they are, largely because of high-quality veterinary care, and the potential stress of the health exams and transportation involved in a move.

The other side holds that the relative freedom of a sanctuary like Chimp Haven, with outdoor spaces for most of the chimps to roam and more natural social grouping, is better even if the chimps have a short time to live.

The difference is both philosophical and practical.

Animal welfare activists, like Laura Bonar of Animal Protection of New Mexico, see the issue as the same as end-of-life care for human beings. Bonar has been one of the leaders in the effort to stop experimentation on chimpanzees and move them to sanctuaries.

She argues that unless a chimpanzee is about to die within days, it should be able to spend its last days at a sanctuary.

“I don’t see anything that should preclude any of those chimpanzees from being transferred,” she said. And, she added, the report of the working group “is just looking at the risk. What about the benefits?”

Veterinarians in research labs see things differently. Charles River Laboratories, which runs the Alamogordo facility under a contract with the NIH, referred me to the NIH for any and all questions.

But at a recent visit to the Yerkes National Primate Research Center, I talked to Joyce Cohen, a veterinarian and associate director of animal resources there, who is not involved in the NIH process because Yerkes owns its chimps. She argued that the care of chimpanzees at Yerkes and other research institutions has many benefits.

In a recent email, she followed up on those comments. “Based on my knowledge of research centers and sanctuaries that care for chimpanzees,” she wrote, “the differences in housing between the two settings are limited.”