Egg Flotation (Bird Husbandry & Management -
& Management / Bird
Husbandry and Management / Incubation of Birds /
||See also: Candling
||Egg flotation is a technique used in
monitoring the development of chicks within eggs.
- A mild disinfection solution (e.g. 10% povidone iodine) safe for use with eggs
should be used, at 43°C (110°F).
- The egg should be placed gently into the liquid and watched.
- A fresh egg will sink (total density is higher than water).
- An egg which is some way through incubation will float (total density is lower
than water), with the blunt end, containing the air cell, uppermost.
- An egg which is decomposing and contains much gas will float very high (as much
as half out of the water), on its side.
- Movement may be detected in a floating egg after approximately two thirds of the
total incubation time (e.g. by 21-22 days of incubation in crane eggs; B115.4.w1).
- The egg should be removed from the disinfectant after a maximum of one minute and
returned to incubation.
|Appropriate Use (?)
- Mainly used with eggs in which a thick shell and/or shell pigmentation makes
candling difficult, or in situations where a suitable light source for candling is not
- May also be used as an adjunct to candling.
- If no movement is seen on the first flotation, the procedure may be
repeated one or two days later.
- Eggs which fail to pip when expected may be floated to determine if the
chick is still alive.
|Complications / Limitations / Risk
- Flotation in cool water may cause the contents of the egg to contract and
draw bacteria into the egg.
- Flotation for too long risks asphyxia and overheating of the embryo.
|Equipment / Chemicals required and Suppliers
||Water, disinfectant, method
of heating water/keeping it warm, thermometer to monitor water temperature, suitable
|Expertise level / Ease of Use
||Not difficult to perform,
but experience makes interpretation easier.
|Cost / Availability
|Legal and Ethical Considerations
||Flotation for too long may
result in asphyxia and overheating of the embryo.
||B106, B115.4.w1, V.w5
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