The NFL has been asked about the research project, which was funded by the Department of Agriculture and would have included data on the number of pigs slaughtered in the league over the past 15 years.
The study is expected to be completed by May.
But some NFL owners have expressed concerns that the study could reveal the league’s poor record in animal welfare.
NFL commissioner Roger Goodell said earlier this month that he hopes to finish the study by the end of the year.
“It’s time to finish this study.
We’ve been working on it for a number of years,” Goodell said.
“The goal is to get this done and then we’ll have a report on how it works and then maybe some of the decisions that we make.”
Goodell added that he had not yet heard from the NFLPA about the study.
He said the NFL will make any changes necessary.
The NFLPA, which is representing the NFL owners and is leading the effort to get the study completed, said it was pleased with the NFL commissioner’s response to the issue.
“We look forward to finishing this important study on the progress that the league has made to improve the welfare of its players,” the union said in a statement.
The league said the study will look at whether the NFL can do better on animal welfare issues, including the treatment of the animals in stadiums and on the field.
Goodell said last month that the NFL would “continue to take steps to improve animal welfare,” but he said the league still needed to do a better job with its animal welfare practices.