Table 1.
Variable | Description of variable | Number of farms |
Manure spread on fields in summer seasonb | Yes | 11 |
No | 17 | |
Manure spread on fields in winter seasonb | Yes | 9 |
No | 19 | |
Manure stored on farm at any time of year | Yes | 10 |
No | 18 | |
Other domestic livestock on farm | Yes | 9 |
No | 19 | |
Other commercial poultry on farm | Yes | 10 |
No | 18 | |
Farm has all-in-all-out policy | Yes | 18 |
No | 10 | |
Farm water source | Non-official | 17 |
Non-official treated | 4 | |
Official | 4 | |
Official treated | 3 |
a Only farms with complete data for all variables are included
b Variables are highly correlated (τb ≥ 0.8)