This article will focus on assessment of chick quality based on appearance by feathering. The first article in this series deals with the general baseline of chick quality, “how can one be sure an issue is incubation related”, whilst the second article deals with the analysis of navels.

The feathering of day-old chicks is a vital indicator for total chick quality. This article discusses the most commonly seen issues of poor feathering and where to look for the potential causes. This will assist you in the continuous improvement of chick quality in your hatchery.

What is optimal appearance?

Chicks should have a uniform appearance with clean and dry feathers free from any materials, such as egg yolk and contaminated fluid meconium. The feathering on the head and neck of the day-old chicks is also important.

Causes of poor feathering

The following issues of poor feathering are commonly seen in the field. Each issue is associated with a potential cause.

Wet feathers

Wet feathers are often related to an incorrect temperature during the late setter cycle or during the transfer period. Generally, 100.0°F (37.8°C) egg shell temperature is optimal for incubation.

However, for very young small eggs (with a low volume to surface ratio), 100.0°F egg shell temperature can result in excessive cooling. Whilst for very old large eggs (with a high volume to surface ratio), 100.0°F egg shell temperature can result in inadequate cooling and overheating.

Different breeds have different heat production curves. The heat production curve during incubation is also influenced by a number of hatchery specific factors: days of storage, pre-heating conditions etc.

It is important to fine-tune the incubation profile to have an optimal egg shell temperature during incubation. A real time egg shell temperature monitoring and controlling device, such as OvoScan™, is critical to ensure the correct egg shell temperature. This will result in a good hatch timing and hatch window, which will limit the amount of chicks with wet feathers at take-off.

An incubator that is set with eggs that have a wide variety in storage times, will result in a wide hatch window where the late hatchers will still have wet feathers at take-off.

It is important that the incubators receive preventive maintenance to ensure that the machines are always working correctly during incubation.

Dirty feathers

Early hatches and/or delayed take-off results in dirty chicks (chicks covered with meconium).

In older flocks, a too high egg temperature after transfer is not unusual due to inadequate cooling. High temperature after transfer increases movement in the baskets. When the infertile or contaminated eggs are not removed during transfer, these eggs can be damaged and broken by the movement of the chicks and this can result in dirty chicks.

Dirty chicks

Poor uniformity of chick colour

Large hatch windows can result in a general poor uniformity, what can also be seen in a poor uniformity of chick colour. Large hatch windows can be induced by poor setter uniformity or incorrect loading of the setter according to flocks with a different heat production. This is often the case with very old machines or with multi-stage incubation.

Poor breeder house conditions or reduced collection times in the breeder house will contribute to this.

Flat feathering on head and neck

Either too high or too low temperatures during the last days of incubation contribute to flat feathers on head and neck. It is key to manage a good feathering by using the correct air temperatures related to the heat production of the chicks.

Flat feathering

Other key elements

• Increased flock age: when the flock age increases, the egg shell quality of the hatching eggs reduces. A reduced egg shell quality can increase the number of broken eggs in the baskets. Hatching eggs with an increased flock age have a higher risk of contamination as well.
• Increased storage time: increased storage time or a wide variety in storage times of different eggs set in 1 machine, results in a wide hatch window. If prolonged storage is necessary, it is ideal to perform a heat treatment during storage (SPIDES) with the BioStreamer™ Re-Store. This will limit the early embryonic mortality and results in a narrow hatch window.
• Candling at transfer: it is advised to remove all infertile eggs and dead embryos at transfer. This will prevent those eggs from breaking in the hatcher when the chicks are moving around or during take-off because of the automatisation. This will result in much cleaner chicks. Removing the ‘bangers’ or high contaminated eggs is also very important since they increase the risk of cross-contamination and yolk sac infection significantly.
• Automatisation: automatic take-off and chick handling needs strict attention in both set-up and maintenance practices to ensure everything is running smoothly and chicks are feeling comfortable. It is strongly advised to perform regular basic checks and observe animal behaviour to ensure an optimal operation.
• Vaccination protocol: it is advised to change the needles on a regular base (recommendation dependent on supplier) and ensure a correct set-up of the vaccination device. Less accurate vaccination can lead to blood on the neck which can induce neck pecking.

Summary