INDIANAPOLIS (AP) — Frigid temperatures are hampering efforts to euthanize turkeys at several southwestern Indiana farms where a strain of bird flu was found.

Indiana State Board of Animal Health spokeswoman Denise Derrer says low temperatures have frozen the hoses that carry a foam used to suffocate the flocks. State and federal workers are instead using carbon dioxide gas or killing them manually with a device that delivers a fatal head injury.

Derrer says workers are moving as fast as possible to kill the birds to prevent the virus from spreading.

Nearly 120,000 turkeys have been killed on four farms, with about 121,000 turkeys on six farms left to euthanize.

The H7N8 strain is different than the H5N2 virus that led to the deaths of 48 million birds last summer.