Safety Instructions
The procedure described below should be performed by qualified personnel
only, because data must be collected in an operating Pas Reform incubator in
which every section of 19,200 hen eggs is fully loaded with four trolleys of
eggs.
When measuring trays from trolleys at the side of the fan, only the
trays should be taken out, without displacing the trolley, thus avoiding the
need for personnel to come too close to the fan.Measurements taken in a
machine which is turned off will result in unreliable data because eggshell
temperatures change immediately when the airflow is nil.
A. Eggshell temperature of individual eggs
1. Read the thermometer instruction guide.
2. Before starting, the thermometer should be warmed in the incubator for
15 min (if this is not done, measurements will be inaccurate).
3. Make sure that the plastic cover (lens filter) is on the thermometer's
infrared probe (the thermometer will not function without this filter).
4. Place the infrared probe on the eggshell, just under the air chamber
(measuring on the air chamber gives a difference of 0.5°F).
5. Measure with the infrared probe right on the eggshell (measuring at the
wrong angle gives 0.5 - 1.5°F deviation).
B. Eggshell temperature of a representative sample
Measure a row of 15 eggs in the middle of a setter tray. The mean
temperature of eggs with living embryos is used as a reference for eggshell
temperature in that specific tray.
1. Select 1 setter trolley per section of 19,200 hen eggs in a Pas Reform
incubator (selecting a trolley at the corridor side is the most convenient).
2. Measure the eggshell temperature of a row of eggs in the middle of
trays 3, 9 and 14 (from the top). This means that in one particular position
you have 15 eggs in a row at the top, 15 in a row in the middle and 15 in a
row at the bottom.
3. Measure the eggshell temperature of these eggs as described under A.
4. Take the mean of these 45 eggs.
C. How to use the data
1. For each trolley you now have the average temperature of all 45 eggs
located in different trays. This average temperature is defined as the
reference eggshell temperature on that day of incubation.
2. If the eggshell temperature deviates too much from the desired embryo
temperature, the incubator temperature setpoint can be adjusted.
The right
temperature depends on breed and maternal age and is usually provided by the
breeding company. In general it can be stated that the average eggshell
temperature must be 37.8 - 38°C (100 - 100.4°F) during the first 2/3 of
incubation. The average eggshell temperature should not exceed 38.5°C
(101.3°F).