*2.4. Instrumentation*

Temperature and relative humidity (RH) (Hobo U23 Pro v2, −40 ◦C to 70 ◦C, ± 0.2 ◦C, and 0 to 100%, ± 2.5%, Onset Computer Corporation, Bourne, MA, USA) were recorded continuously at 25 locations throughout the trailer with T recorded at additional 20 locations (DS1921L Thermochron, ± 0.5 ◦C, Maxim Integrated, Sunnyvale, CA, USA). Air speed were measured by six anemometers (Kestrel 4000; accuracy ± 0.1 m s<sup>−</sup><sup>1</sup> from 0.4 to 40 m s<sup>−</sup>1, Minneapolis, MN, USA) on two modules. Before each scheduled monitoring campaign, data loggers were installed at pre-determined module locations on empty trailers using cable ties at the processing plant (Figure 3a,b). Nine thermal loggers occupied each of the five vertical cross-sections (Figure 4). Temperature, humidity and wind were measured every 30 s. Times of departure from farm to the processing plant were recorded using a GPS unit (eTrex 20, Garmin, Olathe, KS, USA) that logged waypoints every second, downloaded after each trip.

**Figure 3.** (**a**) Thermal and wind dataloggers secured on curbside of a transport module during a monitoring campaign. (**b**) Diagram of instrumented transport drawers showing loggers on curb side, midline and driver side. The interior loggers consist of those on the midline, while exterior loggers consist of those on driver and curb sides.

**Figure 4.** Schematic of an industry-standard drop deck poultry trailer loaded with 20, 10-door modules. Dataloggers (shown as orange dots) for temperature were installed as a 5 × 3 × 3 grid on the trailer. Three horizontal planes along height are Top, Middle, and Bottom. Three longitudinal planes along width are Driver, Midline and Curb.
