ShapeShapeauthorShapechevroncrossShapeShapeShapeGrouphamburgerhomeGroupmagnifyShapeShapeShaperssShape

Empty Shells – a Valuable Source of Information

by 5m Editor
13 April 2012, at 12:00am

Empty egg shells can give valuable information to the hatchery, according to Gerd de Lange of Pas Reform.

On hatch day, unhatched eggs, dead and culled chicks and empty shells are inevitably produced as hatchery waste. It is generally accepted that unhatched eggs and dead or culled chicks can be used to evaluate the incubation process, to help determine where improvements can be made. Empty egg shells are usually overlooked. But these also form a valuable source of information for the hatchery.

Empty shells can provide additional information about the pulling time of the chicks and their hatching conditions. When empty shells are crushed in the hand, the dryness of the shell membranes can be judged. Pulling time and hatching conditions are good if the membranes crumble in your fist without falling apart into small pieces. When the membranes completely stay together and do not crumble, they are still too moist, indicating that the chicks were pulled too early.

In this scenario, one would expect also to see some partially wet chicks – or even externally pipped chicks still alive. The membranes falling apart into small pieces indicates that pulling time was too late or that relative humidity may have been too low during hatching, possibly due to excessive ventilation. If pulling time was too late, a lot of meconium (the greenish droppings produced by the chicks) will also be observed on the empty shells.

The height of pipping is an indication of weight loss during incubation. If weight loss was insufficient, the air cell remains small and the chicks are forced to pip high. Some chicks will not be able to pip at all and will drown inside the egg. The correct height for pipping is roughly at half, or just above half, the height of the egg (see picture below). Exposed to ideal hatching conditions, the chicks will pip the rest of the shell neatly in a circular manner. Rough or incomplete pipping is an indication of sub–optimal hatching conditions.

At days 11 to 12 of incubation, the chorio–allantoic membrane reaches the sharp end of the egg. If the albumen sac is too large due to insufficient weight loss, this membrane cannot reach the sharp end and will not be closed. Insufficient weight loss is typically caused either by too low a temperature or excessive humidity. Observe whether or not the chorio–allantoic membrane is closed by looking inside the bottom part of the empty shells. If there was overheating during the last days in the setter or in the hatcher, excessively thick and clearly visible blood vessels will be observed.

Advice

  • Judge the accuracy of pulling time and hatching conditions by crumbling empty shells in your fist and by checking the amount of meconium on the egg shells.
  • Check the height and manner of pipping to judge whether weight loss during incubation was sufficient.
  • Check the inside of the empty shells for signs of insufficient weight loss during the first half of incubation, e.g. blood vessels not reaching the sharp end of egg.
  • Observe the inside of the empty shells for signs of overheating, e.g. excessively large and clearly visible blood vessels.
  • Use information obtained from assessing the empty shells in conjunction with other observations to avoid hasty or incorrect conclusions.
April 2012