HUADE INSIGHTS | Why What Really Determines a Chick’s Future May Happen Before Hatch, Not After?

Reference 

Kim E, Akhtar N, Li J, et al. In ovo feeding of epidermal growth factor: embryonic expression of intestinal epidermal growth factor receptor and posthatch growth performance and intestinal development in broiler chickens. Poultry Science, 2020, 99: 5736–5743.

Statement

This article is a translated and condensed summary based on the above review article. The content has been reorganized for scientific communication and educational purposes and does not represent the complete views of the original publication. Readers are encouraged to consult the original article for comprehensive information.

Many people believe that a chick’s growth truly begins the moment it hatches and starts eating feed.

In fact, how fast it grows, how efficiently it converts feed into body weight, and how healthy its gut remains throughout its life are all partly determined before the chick even hatches. If we compare a broiler’s life to a marathon, the final few days of incubation, together with the first 10 days after hatch, are more like the starting phase that can determine the outcome of the race. This is a very short period, yet it is far more important than many people realize.

Let’s start with two numbers.

The first number is 10 days. The first 10 days after hatch are the period of most rapid intestinal development in broiler chicks. During this time, the small intestine can account for approximately 7% of the chick’s total body weight, significantly higher than at any later stage. In other words, at the very beginning of life, the chick’s body prioritizes building the gut—not muscle—the organ system responsible for nutrient digestion and absorption.

The second number is 30 days. Research teams from the University of Guelph and the University of Manitoba in Canada have proposed an interesting perspective: for a broiler that eventually reaches a market weight of approximately 2.5 kg, the 21-day incubation period plus the first 10 days after hatch together account for roughly half of its entire production cycle.

Many problems affecting production performance do not actually emerge during the grow-out period. In many cases, the groundwork has already been laid during the earliest stages of life. This is one of the reasons why an increasing number of studies worldwide have turned their attention back to early-life nutrition in recent years.

Every day, poultry producers closely monitor feed intake, average daily gain (ADG), and feed conversion ratio (FCR). Yet few stop to consider a question that comes even earlier:

Before a chick takes its first bite of feed, is its gut truly ready?

Before and After Hatch, the Gut Has to “Switch Fuels”

During the final days of incubation, the developing chick undergoes a critical metabolic transition. Inside the egg, the embryo relies primarily on the yolk for energy, with fatty acids serving as a major fuel source. Once it hatches, however, it is suddenly faced with a completely different nutritional environment: a corn- and soybean meal-based diet, where carbohydrates become a major source of energy.

This is far more than simply switching from one type of food to another. It represents a comprehensive transition in the digestive system. The intestinal villi need to elongate rapidly, new epithelial cells must continuously proliferate and differentiate, and digestive enzyme systems need to become established as quickly as possible, enabling the gut to efficiently digest and absorb nutrients from external feed

When this transition proceeds smoothly, chicks can establish feed intake capacity more rapidly and utilize nutrients more efficiently. But if this critical window is missed, even increased nutritional inputs later on may not be enough to fully compensate for the gap created during early life.

This is also why more and more people in the poultry industry are beginning to explore an intriguing question: Can we help the chick complete this “preparation work” before it even hatches?

The idea may sound bold, but it has actually been studied by the scientific community for many years. One area that has attracted particular attention is EGF (Epidermal Growth Factor).

EGF is a naturally occurring bioactive protein found in mammalian colostrum and milk. It is a small protein consisting of 53 amino acids. Extensive research has shown that EGF can promote the proliferation, differentiation, and maturation of intestinal epithelial cells, which is why it has long attracted interest in studies of intestinal development in neonatal animals. In mammals such as piglets, substantial evidence has accumulated supporting the role of EGF in promoting intestinal development. But what about chickens? Can EGF exert a similar effect in poultry, and if so, is earlier intervention more beneficial?

Ultimately, whether a functional ingredient can deliver a real biological effect comes down to three fundamental questions:

Is there a biological target? Can it act at the right time? And can it actually reach the target?

Many products perform remarkably well under laboratory conditions, yet their effects are difficult to reproduce in commercial production. The problem is often not whether the ingredient can work, but whether it can reach where it needs to work.

And that is exactly the third question this paper focuses on.

A Clever Way to Deliver It

Researchers came up with a rather clever approach. They found that during the late stages of incubation, chicken embryos actively swallow amniotic fluid, which eventually enters the developing gastrointestinal tract. In other words, if a nutrient or bioactive compound could be delivered into the amniotic cavity in advance, the embryo would naturally ingest it—essentially receiving an oral nutritional supplement before hatch.

This technique is known as in ovo feeding.

At first glance, it seemed almost like a perfect strategy: deliver a growth factor that supports intestinal development at the critical stage of gut maturation. The timing appeared right, and the delivery route seemed appropriate. In theory, the outcome should have been promising.

To investigate this, a Canadian research team designed two sets of experiments.

The first experiment examined whether EGF receptors in the embryonic intestine could respond to the EGF signal.

The second experiment followed the hatched chicks for another 21 days to determine whether EGF supplementation could actually improve growth performance, feed conversion ratio (FCR), and intestinal development.

However, the actual results turned out to be quite different from what the researchers themselves had expected.

HUADE Insights

In commercial poultry production, we often focus our attention on what happens after chicks hatch, while overlooking what has already taken place before hatch.

The first few weeks of life are not simply a period of “starting to grow.” They represent a critical window that can shape the chick’s subsequent growth potential and production performance.

What truly deserves our attention is not only what nutrients we provide, but when we provide them, how we deliver them, and whether they can reach the right site at the right time.

EGF is just one example within this emerging field of research. But the questions it raises are worth continued exploration across the poultry industry.