Yeah, each broiler house can hold ~20-50k chickens (depending on size). A few million chickens is a pretty large operation. Most farms around here have about 20 houses max.
Even aside from those particular birds, the shortage of chicken and eggs from bird flu has driven prices way up. Fewer wings to go around, so parties bid up what's available.
The Dispatch reported that the entire flock will be culled, with the remains isolated, to help prevent further spread.
Kind of unfortunate that they can't figure out which ones got sick and cull just those. Would be nice to move towards chickens that are more-resistant to the flu, but that can't happen unless the vulnerable ones are selected against in terms of survival. An across-the-board cull doesn't do that.