Table. 2.
Predictors used in the fecal, soil, and processing product whole carcass rinse (WCR) random forest model.
| Variable | Description | Levels/unit |
|---|---|---|
| AvgNumBirds | Average number of birds that the farm handle in 1 year | 3 levels: <1000, 1000-10,000, >10000 |
| AvgNumFlocks | Average number of flocks that the farm handle in 1 year | 6 levels: 1, 2, 3, 4, 5, 16 |
| YearsFarming | Number of years the farm had been operating at the time of sampling | 2 levels: <10, ≥10 (years) |
| EggSource | Source of broiler eggs | 6 levels: company A, B, C, D, E, F |
| BroodBedding | Type of bedding broilers received during brooding | 3 levels: pastured based brooder (PB), wood shavings (WS), saw-dust/shredded paper (SDSP) |
| BroodFeed | Up to top 3 sources of protein in brooding feed | 6 levels: barley, wheat, oats (BWO); corn, soy, wheat (CSW); wheat, corn (WC); wheat (W); corn, soy, oats (CSO); peas, corn, oats (PCO) |
| BrGMOFree | Was the brood feed GMO free? | 2 levels: yes (Y), no (N) |
| BrSoyFree | Was the brood soy free? | 2 levels: yes (Y), no (N) |
| BrMedicated | Was the brood feed medicated? | 2 levels: yes (Y), no (N) |
| BroodCleanFrequency | How often the brooding area was cleaned? | 6 levels: 3Days, all in/all out (AIAO), daily, deep litter method (DLM), mobile, weekly, yearly |
| AveAgeToPasture | Average age broilers were put on pasture | 2 levels: 3 weeks, 4 weeks |
| PastureHousing | Type of pasture housing environment | 4 levels: chicken tractor (CT), chicken tractor with fencing (CTF), chicken tractor free ranger (CTFR), chicken tractor with fencing (2 tractors; CTF2) |
| FreqHousingMove | How often the pasture area was moved? | 2 levels: daily, every 2 days |
| AlwaysNewPasture | Was the pasture always moved to a brand-new pasture area? | 2 levels: yes (Y), no (N) |
| PasturedFeed | Up to top 3 sources of protein in pasture feed | 7 levels: barley, wheat, oats (BWO); corn, soy, wheat (CSW); wheat, corn (WC); wheat (W); corn, soy, oats (CSO); corn, cotton seed mill, wheat (CMW); peas, corn, oats (PCO) |
| PaGMOFree | Was the pasture feed GMO free? | 2 levels: yes (Y), no (N) |
| PaSoyFree | Was the pasture feed soy free? | 2 levels: yes (Y), no (N) |
| PaMedicated | Were broilers medicated while on pasture? | 2 levels: yes (Y), no (N) |
| LayersOnFarm | Were layers present on the farm? | 2 levels: yes (Y), no (N) |
| CattleOnFarm | Were cattle present on the farm? | 2 levels: yes (Y), no (N) |
| SwinOnFarm | Were swine present on the farm? | 2 levels: yes (Y), no (N) |
| GoatsOnFarm | Were goats present on the farm? | 2 levels: yes (Y), no (N) |
| SheepOnFarm | Were sheep present on the farm? | 2 levels: yes (Y), no (N) |
| WaterSource | Water source for broilers during grow-out | 3 levels: public, rain, well |
| FreqBirdHandling | How often chickens were handled on pasture? | 2 levels: daily, only if needed (OIN) |
| AnyABXUse | Were antibiotics ever used on the broilers? | 2 levels: yes (Y), no (N) |
| LengthFeedRestrixProcess | Length of feed restriction before processing | 5 levels: 8, 12, 16, 18, 24 (hours) |
| DayOfYear | Day of the year samples were collected on | Numeric (days) |
| FlockAgeWeek | Age of flock at time of sampling | Numeric (weeks) |
| Breed | Breed of broilers used | 3 levels: freedom ranger (FR), Cornish cross (CC), red ranger (RR) |
| Flocksize | Number of birds in the sampled flock | 3 levels: 0-100, 100-500, >500 |
| AnimalSource | Type of the animals | 4 levels: broiler, layer, swine, cattle |
| ProcessingTypea | Where the broilers were processed? | 2 levels: farm, plant |
| SkinOnOffa | Skin on or off processing facility | 2 levels: on, off |
| ScalderTempCab | Temperature of water (ºC) used during scalding of birds during processing | 7 levels: 55, 60, 63, 65, 71, 82, none |
| RinseWaterSourceab | Source of water used for carcass rinsing during process | 2 levels: public, well |
| RinseWaterChlorab | Was the rinse water chlorinated? | 2 levels: yes (Y), no (N) |
| ChillingMethoda | Type of chilling method used for carcasses after processing | 2 levels: water, air |
| TransportTimeab | Length of time to transport broilers to processors (if necessary) | 4 levels: 0.5, 3, 3.5, 5 (hours) |
| StorageTempCab | Temperature that carcasses were stored before reception by customer | 2 levels: −20, 4 (ºC) |
| StorageTimeDab | Amount of time carcasses were stored before reception by customer | Numeric (days) |
a
Variables were used in the WCR-P model.
ab
Variables were used in the WCR-F model.