DES MOINES, Iowa (AP) – Iowa egg farms are bouncing back from last year’s bird flu outbreak but rebuilding flocks with millions of new egg layers is taking time as the industry predicted. The latest U.S. Department of Agriculture report released Friday shows Iowa’s population of egg-laying hens at 37.9 million in December, up 6 percent from November but still 37 percent below the year-ago figure.

Iowa farms produced 812 million eggs, up 11 percent from the previous month but down 44 percent from December 2014. The bird flu last summer killed 48 million birds nationwide including 24 million Iowa laying hens. Farmers have replenished flocks but expect it to take most of this year to reach full production again.

U.S. egg production in December was 8 billion, down 8 percent from a year ago.