(Radio Iowa) – Iowa Ag Secretary Mike Naig says nearly 13 million poultry animals have been killed in Iowa so far to try to prevent the spread of bird flu.

Naig says in the bird flu outbreak of 2015, the virus spread from facility to facility, but it appears bio-security measures at large operations are working and officials believe this year’s round of bird flu is being spread by wild birds.

Naig made his comments today (Friday) during taping of “Iowa Press” which airs tonight (Friday) at 7:30 on Iowa P-B-S.