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Optimize your value chain (5) – How to recognize good and bad humidity regulation in the incubator

We explained why and when CO2 levels should be raised or lowered last month. Today we describe how you can recognize signals of good and bad humidity regulation in the incubator. We will also check if your humidity management is still in great shape.

Regulating humidity is key for egg weight loss and will get you the most profitable chicks, allowing you to optimize your value chain. Losing water through the egg shell allows the embryo to build up an internal air cell that is used for the start-up of pulmonary respiration after internal pipping.

The material of the egg shell is impermeable to gases or water so that the contents do not dry out. Therefore, moisture exchange takes place through its pores. The amount of water loss – and consequently weight loss – depends on the difference of relative humidity between the inside and the outside of the egg. At the beginning of an incubation cycle, the relative humidity of the egg is 100%. The bigger the difference between the inside of the egg and its surroundings, the more moisture is lost. Therefore, high levels of humidity will limit the amount of weight loss, while low levels of humidity will enhance weight loss. Petersime’s incubators have a sealed cabinet that allows a natural build-up of the humidity. In dry climates, humidity can be increased with a water spray nozzle.

How much weight loss should be achieved and when

From set to hatch, the chick yield (the ratio of chick weight divided by egg weight) should be around 68%. The ideal weight loss profile is found in nature and follows a non-linear rise. During the first nine days, the egg should lose weight slightly. Because the mother hen sits on her eggs very often, the humidity around the eggs is quite high, resulting in low weight loss.

After this first stage of incubation (remember that the hen leaves the nest more regularly from day 10 onwards, allowing more fresh air to surround the eggs, see “Optimize your value chain (2) – Nature’s guidance to maximizing the genetic potential of the egg”), the embryos lose weight at a higher speed, because the relative humidity around the eggs is lower, until they have reached the ideal weight loss point and are prepared to hatch. 

A non-linear weight loss concept as found in nature

Nowadays, with Embryo-Response Incubation™ technology, egg weight loss is measured continuously and humidity levels are automatically adapted accordingly by ventilating the room so the embryos develop well.

How to recognize good and bad humidity regulation in the incubator

The egg should have lost the correct amount of water by the internal pipping phase. If it has retained too much water, the embryo may be too weak to proceed to external pipping. Chicks that have not lost enough moisture have hard stomachs and sit low in the baskets. They are lethargic and unreactive.

If it has lost too much water, the embryo risks dehydration. Red hocks are often an indication that the chick did not lose enough weight during the incubation process. At the farm, these birds do not go looking for food and water.

In comparison, a bird that has achieved a good weight loss stands tall and inquisitive.

A healthy hatchling standing tall and inquisitive / A lethargic hatchling with red hocks

Checklist for optimum humidity conditions

→ Is the floor of your incubator perfectly level? In case water gets inside the incubator, the water can get out and you avoid unwanted humidity build-up.

→ Do you have leaks somewhere? Check for water leaks to prevent unwanted humidity build-up.

→ Avoid spraying and adding humidity, because this disturbs the temperature distribution in the incubator.

→ Avoid high humidity in the setter room, because this reduces the ability to lose moisture during ventilation.

All parameters together

In the series “Optimize your value chain”, we have discussed what the best way is to add value to the poultry industry chain. Petersime believes that nature should be our guide in this question. We should listen to the needs of the embryos and respond like a mother hen would do. By mimicking natural behaviour, we do not only safeguard the welfare of embryos in the best possible way, we also hatch the best performing chicks with the lowest mortality rates. We can bring quality chicks with added value to the poultry chain like never before. Now we know that the most decisive factors in the incubation process are temperature, CO2 and egg weight loss. Petersime has developed different incubation profiles for different types of fowl and flock ages. 

Example of an incubation profile

All these parameters should be monitored and controlled together to obtain the most profitable chicks for everybody in the chain. Does this mean we have finally found the best way of incubating? That we have reached the end? No. At Petersime, we are investigating the influence of other variables on the incubation process by studying nature. The future of incubation promises to be more interesting than ever before. 

Read the other articles in the series “Optimize your value chain”

1.       The growing concern to deliver quality

2.       Nature’s guidance to maximizing the genetic potential of the egg

3.       Are your temperature conditions still in great shape?

4.       Why and when CO2 levels should be raised or lowered