EFFECTS OF STRUCTURAL AND STACKING CONFIGURATION OF CONTAINERS FOR TRANSPORTING CHICKS IN THEIR MICROENVIRONMENT

Breeder (layer) chicks in transit are vulnerable to oxygen shortages t hat stem from the lack of mechanical ventilation in holding areas such as warehouse and cargo compartments of aircraft. Such vulnerable peri ods tend to occur around departure time of an aircraft when the cargo door is closed but the compartment has not been pressurized, and vice versa upon landing: To maintain the well-being of the chicks, sufficie nt air exchange through the containers is essential during these perio ds. This study examined the airflow rates and internal thermal conditi ons of a commercial chick container as influenced by its structural an d stacking configurations. Specifically a 2x2 factorial arrangement of container structures was examined that consisted of a regular cardboa rd box (62 x 47 x 15 cm) and a box modified by adding extra vent holes (128 vs 92) on the side walls; each type of box was covered with eith er the regular cardboard lid or a modified plastic poultry grid lid. T he effects on airflow rate of vertical distances (VD) from 2.5 cm (cur rently used) to 17.8 cm between the boxes were evaluated with one stac k of four containers. The effects on airflow rate of horizontal distan ces (HD) from 5.1 to 15.2 cm between the stacks were evaluated with fo ur stacks of six containers each. NI/CR electrical heating wires evenl y located above the excelsior bedding were used to simulate sensible h eat production rate (21 W at 30 degrees C) of 88 unfed day-old chicks that are normally held per container. The results revealed that the me asured ventilation rate under the current box structure and stacking a rrangement (averaging 0.013 L/s/chick or 0.028 CFM/chick) seemed suffi cient during cold weather but was considerably below values recommende d for mild to hot weather An improved, practical container structure a nd stacking configuration features the regular container body with the grid lid, 7.6 cm VD between boxes, 5.1 cm HD between stacks linked wi th the existing cardboard spacers. The improved structure and stacking configurations had an average air flow rate of 0.062 L/s/chick. The c orresponding internal temperature rise of the containers relative to t he test room temperature was 3.4, 4.7, 4.8, 5.0, 5.5, and 4.8 K for la yer 1 (bottom layer), 2, 3, 4, 5 and 6 (top layer), respectively, comp ared to 5.5, 8.1, 9.1, 9.8, 9.9, 7.8 K for the current box structure a nd stacking arrangement. Because of the excessive airflow rate and pot ential cold draft for the top layer the original cardboard lid was rec ommended for the top containers.