8/8/2019 La Calidad Del Pollo Depende de La Temperatura

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HATCHERY

Aconsequence of the ongoing selectionof high yield breeds is the increasedvariability in hatchability of eggs from

flocks of different ages. Eggs from young andold breeders differ significantly with respectto size, eggshell conductance and heat pro-duction. To achieve the best hatchability andchick quality, the hatchery manager shouldbe able to incubate each batch of eggs underthe most optimal conditions.

It is generally accepted that an All-In/All-Out or Single-Stage setting has specific ad-vantages in this matter. With All-In/All-Outincubation all eggs are set in the same set-

ter at the same time, which means that ahatchery manager can have greater controlby providing the heat, cooling, air velocity,venting and humidity that is needed for theembryos at the different stages of incuba-tion. Depending on variations in strain ofbreeder, week of lay (size of egg), length ofstorage time and shell thickness (moistureloss), the incubation programme can be ad-

justed by changes in temperature, ventila-tion and relative humidity. This means thatthe climate control of incubators must beflexible with regard to temperature, ventila-tion and humidity set points.

Impact on hatchabilityBiological and physiological research onembryos has shown that temperature is themost critical environmental influence onthe developing embryo. Even minor fluctu-

ations can have a major impacton hatchability and chick quali-ty. A way to improve the incuba-tors temperature programme isto look at the temperature of aspecific number of eggs duringthe different phases of the incu-bation process. Because embryotemperature cannot be mea-sured without destroying theegg, the temperature of the egg-shell is used as a reference. The cheapestand easiest way to measure eggshell tem-perature is with an infrared fever thermo-

meter. It has been proven that, for example,the Braun Thermoscan(with an accuracy of 0.3F) is a practical instrument for suchmeasurements, provided the instrument isused properly. To get a good idea of actualeggshell temperature in a specific incuba-tor, a representative sample of eggs mustbe measured. The procedure given de-scribes (A) how to measure the individualegg,(B) how to measure a representativesample and(C) how to use the data.

A. Eggshell temperature ofindividual eggs

Read the thermometer instruction guide.

Before starting, the thermometer shouldbe warmed in the incubator for 15 min-utes (if this is not done, measurements

will be inaccurate). Make sure that the plastic cover (lens fil-

ter) is on the thermometers infraredprobe (the thermometer will not function

without this filter). Place the infrared probe on the eggshell,just under the air chamber (measuring onthe air chamber gives a difference of 0.5F).

Measure with the infrared probe right onthe eggshell (measuring at the wrongangle gives 0.5 - 1.5F deviation).

B. Eggshell temperature of a

representative sample Measure a row of 15 eggs in the middle of

a setter tray. The mean temperature ofeggs with living embryos is used as a refer-ence for eggshell temperature in that spe-

cific tray. Select one fully loaded setter trolley per

section in an incubator (selecting a trolleyat the corridor side is the most convenient).

Measure the eggshell temperature of a rowof eggs in the middle of trays 3, 9 and 14(from the top). This means that in oneparticular position you have 15 eggs in arow at the top, 15 in a row in the middleand 15 in a row at the bottom.

Measure the eggshell temperature of theseeggs as described under A and write themeasured values on a form.

Take the mean of these 45 eggs.

C. How to use the data For each trolley you now have the averagetemperature of all 45 eggs located in dif-ferent trays. This average temperature isdefined as the reference eggshell tempera-ture on that day of incubation.

If the eggshell temperature deviates toomuch from the desired embryo tempera-ture, the incubator temperature set pointcan be adjusted. The right temperaturedepends on breed and maternal age and isusually provided by the breeding compa-ny. In general it can be stated that the av-erage eggshell temperature must be 37.8 -38C (100 - 100.4F) during the first 2/3 ofincubation. The average eggshell tempera-

ture should not exceed 38.5C (101.3F).

Chick quality andhatchability depend on

incubation temperature

The easiest and most economical way tomeasure eggshell temperature is with aninfrared fever thermometer.

Safety InstructionsOnly qualified personnel should perform the procedure describedbecause data must be collected in an operating machine in whichevery section is fully loaded with trolleys of eggs. When measur-ing trays from trolleys at the side of the fan, only the trays shouldbe taken out, without displacing the trolley, thus avoiding theneed for personnel to come too close to the fan.

Measurements taken in a machine that is turned off will resultin unreliable data because eggshell temperatures change immedi-

ately when the airflow is nil.

WORLD POULTRY - Elsevier Volume 18, No 10.'02 www.AgriWorld.nl 27

To achieve the best possible hatching percentages andthe highest possible quality in day-old chicks, hatcheriesmust create a climate that mimics the conditions in abroody hens nest and create homogeneous temperaturesfor the embryos.

By Marleen Boerjan, Pas Reform, Zeddam, The Netherlands