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Either automatic or hand turning may be used.
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If eggs are turned by hand they should be turned several times per day (minimum five times daily), and always turned an odd number of times so that the egg is on opposite sides for the longest internal (overnight) on alternate nights.
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Eggs should be marked with "O" on one side and "X" on the opposite side, and all turned so that the "O" is uppermost on all the eggs after one turning and the "X" is uppermost after the following turning.
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Eggs should be turned in one direction one day and the other direction the following day (i.e. rotated along their long axis clockwise and anticlockwise alternately). Continual rotation in the same direction may lead to problems such as twisting of the chalazae, rupture of the yolk sac or rupture of blood vessels in the embryo.
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Various means of automatic turning may be used. Eggs may be laid on their sides on rollers which move one way then the other alternately, or on a flat tray with movement provided by the movement of rods one way then the other (or the rods may stay still while the tray moves). An alternate method involves eggs being placed small end downwards in trays which are tilted to 45 degrees one way then 45 degrees the other way.
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N.B. if automatic turning is used, monitoring is required at different times of day to confirm that the eggs are being turned.
