Research Article Access to water and feed in the hatcher increases chick heat production Dr. Carla van der Pol port systems. HatchTech’s research team performed an Years of experience have taught hatchery managers, experiment to quantify the difference in heat production day-old-chick transporters, and poultry farmers which climate between chicks that had received water and feed conditions their newly hatched chicks prefer. However, the immediately post hatch and traditional chicks. world of incubation is changing, and the requirements of the day-old-chick may be changing along with it. One important Experiment: heat production change is the development of systems in which chicks receive 120 Ross 308 eggs that had been incubated for 18.5 days water and feed immediately post hatch. were placed in 4 climate respiration chambers at Wageningen University & Research. Climate respiration In a traditional hatchery, newly hatched chicks do not receive chambers are facilities in which the energy metabolism water and feed until they arrive at the farm. The full onset of live animals can be measured through their respiration. of their growth and development is delayed in this period All eggs were incubated at an eggshell temperature of without feed and water. New systems in which chicks are 37.8°C and were exposed to continuous light. Half of the provided with water and feed immediately after hatching hatched chicks received water and a pelleted feed imme- are becoming the new standard. For example, HatchCare is diately after hatch, and the other half did not receive water HatchTech’s hatcher with light, water, and feed. Providing and feed. The experiment was ended on day 22 after the nutrition immediately post hatch means that a chick can start of incubation, when all chicks had hatched. continue developing. However, this impacts the chick’s physiology. Digestion of feed increases the metabolic rate O2 intake and CO2 output per climate respiration chamber as some of the energy in feed is converted to heat when were measured continuously and used to calculate heat nutrients are digested and metabolized. This results in production (mW/chick; Gerrits and Labussière, 2015). increased heat production. Moment of hatching was recorded for each egg through video observations. At pull time, individual body weights An increase in heat production may have consequences for were measured per climate respiration chamber (for chicks the ideal environment of the chick, and thereby the required with access to water and feed). cooling capacity for the chicks’ hatching, storage, and trans- Gildetrom 25 | 3905 TB Veenendaal | The Netherlands | +31 318 512 511 | [email protected] | www.hatch

Immediate water and feed access Withheld Hatch window Incubation time (days) Figure 1. Heat production of chicks that had access to water and feed immediately post hatch or that did not receive water or feed (Withheld) and total percentage of hatched chickens over time. Higher heat production Heat production increased for all embryos and chicks as the hatching process progressed until embryonic day (E)20:06h (Figure 1). By then, about 90% of all chicks had hatched. The chicks that had access to water and feed continued increasing heat production while the withheld chicks plateaued at about 340...

Ventilation is crucial Along with the increase in heat production, an increase in O2 consumption and CO2 production could be observed for the chicks with access to water and feed compared to the withheld chicks. By the time at which chicks are normally pulled from their incubator, at E21:12, CO2 production was 2 times higher for chicks with access to water and feed (at 1.42 ml/min) than for withheld chicks (at 0.71 ml/min). By E22:00, O2 consumption was 1.80 ml/min per chick for chicks with access to water and feed compared to 1.00 ml/min per chick for withheld chicks. CO2 production was 1.74...