Table 1 Model parameters.

Incubation period

Up to 1 day (shedding after 8 hours, death after one day)

I. Brown (pers. comm); [14, 15]

Survival of virus on seed premises

Up to15 days

[16]

Probability of staff working on multiple premises (Farm size)

0.45 (< 50,000 birds)

0.1 (50,000 to 200,000 birds)

0 (> 200,000 birds)

P. McMullin (pers. comm)

Distance travelled by staff between premises

Up to 35 km

P McMullin (pers. comm.)

Frequency of vet visits

Every 50 days

P. McMullin (pers. comm)

Frequency of manager visits

Every 10 days (non-layer farms)

Every 50 days (layer farms)

P. McMullin (pers. comm)

Probability catching team catches species (multi species farms only)

0.7 Chicken

0.12 Turkey

0.16 Duck/goose

0.01 Other

Calculated from catching company data, where species type available

Probability of catching team, slaughterhouse and owner transmission

0 to 0.2, in steps of 0.01, with additional parameter at 0.001 added.

N/A

Time to detection

2 to 6 days (15 days later for ducks/geese)

Extrapolation from [15–17]