Lohmann Hatchery Guide

42 LOHMANN TIERZUCHT › MANAGEMENT GUIDE 42 PROCESSING OF CHICKS An easy and clear indication of chicks’ condi- tion is the body temperature, which is very important because we don’t want to dam- age the quality of our hatched chicks in take- off and handling. It would be a paradox if any action on embryos in perfect condition, which respected hatcher time, increased the risk of damaging liveability and destroying quality only because of the poor conditions in the processing stage before delivery. At collection, pay attention to rectal tem- perature. It provides very helpful and very ac- curate data, but testing this temperature can damage the rectum of the chicks and some unfortunate chicks may die. For this reason, I prefer take ventral temperature. Remember to take a large sample (many chicks), because the temperature can vary a lot due to size and sexual differences, but our chicks stay within a perfect range of temperatures when: Average chicks’ body temperature Temperature in machine or immediately after hatcher take-out 40.5– 39.5 °C 105– 103 °F Temperature of chicks when relaxing in delivery basket 39.5– 38.5 °C 103– 101 °F During chicks’ selection, sexing, and vac- cination, the body temperature isn’t a valuable piece of data, because the chicks’ external conditions and stress factors in- terfere. It is easy to check temperature visually, because: › › At low temperatures, the chicks huddle together in a corner to try to maintain body temperature and reduce their maximum activity. › › At temperatures which are too high, the chicks open their becks and pant. In this state they lose a lot of humidity and some chicks’ liveability is reduced. They become noisy (cry) and spread their wings to try to reduce body tempera- ture; the fluff looks smooth. Significantly improving air flows and humidity value can greatly help our chicks to regain the right body temperature quickly. At the exit from the hatcher machine, the general environmental conditions are important. We have to remember that this is a delicate phase and that our chicks are stressed about external conditions. Any movement and transport and can scare them, which is why a fast processing can help. LOHMANN TIERZUCHT GmbH varieties of commercial layers are all either colour sexable or feather sexable. These differ- ent processes need different amounts of time (chronological time), which have to be calculated by the hatchery manager in advance, in relation to the number of workers and the distance of delivery. This is done so that the wings develop correct- ly, which means that chicks can be sexed more easily, so error is reduced. In a normal air flow, the recommended temperature that guarantees chicks good room conditions is 25 °C (77 °F) and the recommended relative humidity is around 45–65 %. These values are, of course, rela- tive to the room and the quantity of chicks in the process. In a biosecurity hatchery, the chicks’ pro- cessing room needs a negative pressure, because this condition allows the removal of fluff in a secure way and doesn’t neces- sitate moving from room to room in a dan- gerous condition. This is different for a vac- cination room, which has to maintain as clean an atmosphere as possible, and for a vaccine storage room, which has to stay at a pressure above environmental pres- sure – here it has to be guaranteed that the only exit of air from this room happens when the operator prepares vaccine dilu- tion and injection bags. Chicks’ take-off has to respect the welfare of the chicks and must give the chicks and the operator the best conditions in terms of temperature and oxygen while produc- ing as little fluff and noise as possible. Chicks’ temperature Chicks’ take-off and sexing