WASHINGTON — Two animal welfare groups and dozens of lawmakers are urging the Obama administration to improve humane treatment of poultry at slaughterhouses, citing statistics that show hundreds of thousands of chickens are accidentally dropped alive into scalding tanks every year.

The Animal Welfare Institute and Farm Sanctuary have petitioned the Department of Agriculture’s Food Safety Inspection Service to strengthen humane treatment regulations, by, among other things, banning live birds from the scalding tanks. When things go according to plan, birds are already dead by the time they’re dropped into the tank, but a small percentage miss the automatic knife that is supposed to slit their necks and wind up dying in the tank.

The Food Safety Inspection Service, known as FSIS, and the National Chicken Council, a trade association, stressed that the number of birds who die that way represents a tiny fraction of the billions of chickens that are slaughtered every year.

Georgia, Arkansas, Alabama, North Carolina and Mississippi are the top five states for chicken meat production.

Earlier this month, 68 House members urged Agriculture Secretary Tom Vilsack to scrap a proposed poultry inspection rule that would speed up cleaning and inspecting bird carcasses, known as evisceration. The lawmakers said that would result in more birds missing backup slaughter devices and entering the scalding tank alive. The House members also objected to the rule’s reduction of 500 to 800 inspector positions.

FSIS Deputy Administrator Phil Derfler said that the Agriculture Department “is using the full extent of its legal authority to protect chickens from inhumane conditions because poorly treated birds can present a food safety concern, and it is ethically appropriate for us to do so.”

He said that those efforts led to an all-time low of chickens killed by other than humane methods of .008 percent last year.

“Our goal is always to drive that number as close to zero as possible, and our proposal to modernize poultry slaughter inspection would help do that,” Derfler said.

Birds that die by means other than slaughter are called “cadavers” and not allowed to enter the food supply.