The term "chick quality" is rather vague, as it can refer to various aspects — from directly visible physical traits to hidden ones, such as antibody levels, physiological disorders, infections and nutritional deficiencies, Pas Reform Academy senior hatchery specialist Maciej Kolanczyk explained in a new white paper.
Many of these hidden traits originate long before the eggs reach the hatchery, he said, noting that environmental conditions and time can have a detrimental effect on chick quality. A chick quality score is only a reflection of a temporary status and an expression of current prospects for the farm results, Kolanczyk said.
A good, smooth start is essential and determines the final result, he added, noting that as time passes, farm-related factors start to prevail over those of the hatchery. Nevertheless, vertically transmitted diseases found later on may still adversely affect the hatchery's reputation.
From the hatchery's perspective, he said a good day-old chick is free from physical disorders and shows the following traits: strong, standing on its legs, fluffy (including standing fluff on the head), active but relaxed, clean, open, round eyes, a soft, supple belly, well-closed, invisible navel, not bony, not dehydrated and free of injuries and deformations.
According to Kolanczyk, these traits are related to and correspond with different aspects of incubation and hatchery procedures. While a trait score can have a wide range (e.g., to describe the size of belly or level of fitness), it is best to minimize subjectivity and simplify assessment to a 0/1 system. The trait is either correct or not.
Today’s hatchery business is a mass operation processing thousands of chicks per day, Kolanczyk explained, and a daily hatch frequently consists of many sub-groups (based on flock, age and egg age). A quality control system must be comprehensive, quick, easy and repeatable. It should enable batches to be compared and provide a numerical expression of quality.
As an example, Kolanczyk pointed to the Pasgar Score, which is based on five easy-to-evaluate traits:
1. A strong, well-shaped chick will right itself within three seconds if placed on its back on a flat, non-slippery surface. This ability, which is a reflex, is an indication of its general fitness, Kolanczyk said.
2. The navel should be well closed and invisible. A navel that is dry and skin-colored but convex and rough to the feel is not correct, but it is a lot better than a leaking or hyperaemic navel, he said, adding that following the principle of "correct or not," both forms will score negative.
3. Evaluation of the belly — its size and hardness — requires sensitivity and experience. Context is important. As belly size is related mostly to egg weight loss, some extra water reserves can be an advantage for chicks when batches planned delivery time or distance is long.
4. Red hocks suggest insufficient weight loss (big belly) or/and overheating.
5. A red spot above the beak or bleeding from the nostrils indicate overheating; a dirty beak is a sign of metabolic disorders related to egg weight loss.
Kolanczyk finished with the following points:
- Decide what to score: quality at hatch or quality of saleable chicks?
- Keep records of quality scores, and analyze trends.
- Identify the main problems, and use this information to correct incubation programs and hatchery procedures.