Chickens and pigs digest starch from grain-based food equally well, but their digestive systems work very differently to achieve the same result. According to Gram Research analysis, chickens have a larger front digestive tract and longer small intestine relative to body weight compared to pigs, yet both animals break down similar amounts of starch. This research shows that different animal species can accomplish identical digestive outcomes through distinct physiological mechanisms and timing patterns.
Chickens and pigs can break down the same amount of starch from grain-based food, but they do it in completely different ways. Researchers compared how these two animals process maize-based feed by tracking food movement through their digestive systems. They found that chickens have a larger front section of their digestive tract and a longer small intestine relative to their body size compared to pigs. Despite these physical differences, both animals end up digesting similar amounts of starch. This research helps farmers and nutritionists understand how to feed different animals more effectively and may inform better feeding strategies for livestock.
Key Statistics
A research article published in the British Journal of Nutrition in 2026 comparing 14 young animals found that chickens had significantly heavier front digestive tracts and longer small intestines relative to body weight than pigs, despite achieving comparable starch digestion levels.
Research tracking food movement through digestive systems of chickens and pigs using dual markers revealed that both species achieved similar starch digestibility from maize-based diets despite relying on different digestive kinetics and physiological mechanisms.
A controlled study examining seven pairs each of 24-day-old chickens and 50-day-old pigs fed identical grain-based diets found that physical differences in digestive tract size and small intestine length did not prevent equivalent starch digestion between species.
The Quick Take
- What they studied: How chickens and pigs digest starch from grain-based food differently, even though they end up breaking down similar amounts
- Who participated: Seven pairs of young chickens (24 days old) and seven young pigs (50 days old), each pair eating the same maize-based diet
- Key finding: Chickens and pigs achieve similar starch digestion levels, but chickens have a larger front digestive tract and longer small intestine relative to body weight, meaning they use different physical structures to accomplish the same digestive goal
- What it means for you: Understanding these differences helps farmers feed chickens and pigs more efficiently based on how their bodies naturally work. For consumers, this research supports better animal nutrition practices, though it doesn’t directly affect human diet choices
The Research Details
Researchers fed seven pairs of young chickens and seven young pigs the exact same grain-based food for 10 days. The food contained special tracking markers (one solid, one liquid) so scientists could follow how it moved through the animals’ digestive systems. After the animals fasted for 5 hours, they were given 1 hour to eat, then their digestive tracts were examined at 2, 4, 6, and 8 hours after feeding. Scientists collected samples from all the different sections of the digestive system before the large intestine, paying special attention to the small intestine by dividing it into four equal parts.
This careful tracking method reveals not just how much food gets digested, but where and when digestion happens. By comparing two different animal species eating identical food, researchers can identify which digestive differences are truly important for breaking down nutrients. This approach is more reliable than simply looking at final digestion results without understanding the process
The study used a controlled design where both animal types received identical diets and were sampled at multiple time points, which strengthens the reliability of comparisons. The use of two different tracking markers (solid and liquid) provides more complete information about food movement. However, the study involved relatively small numbers of animals, so results should be confirmed with larger studies
What the Results Show
Chickens had a significantly heavier front section of their digestive tract (the part before the small intestine) and a longer small intestine relative to their body weight compared to pigs. Despite these major physical differences, both animals achieved comparable levels of starch digestion from the maize-based diet. This means that even though chickens and pigs are built differently, they can break down similar amounts of grain-based food. The different physical structures appear to accomplish the same digestive outcome through different mechanisms and timing.
The research revealed that chickens and pigs rely on different kinetics, which means the speed and location of digestion varies between species. Chickens appear to process food through their digestive system differently than pigs, with timing differences in how quickly food moves through various sections. These differences in digestive timing and location represent distinct physiological strategies that both lead to effective starch breakdown
This research builds on existing knowledge that different animal species have adapted digestive systems suited to their evolutionary needs and natural diets. The finding that similar digestive outcomes can be achieved through different physical structures and processes supports the broader understanding that nature provides multiple solutions to the same nutritional challenge. This study provides specific evidence for how this principle works in practical livestock feeding situations
The study used relatively small sample sizes (seven pairs of each animal type), which means results should be confirmed with larger studies before making major feeding changes. The animals were young (24-day-old chickens and 50-day-old pigs), so results may not apply to older animals. The study only examined one type of grain-based diet, so it’s unclear whether these digestive patterns hold true for other feed types. Additionally, the study was conducted in controlled laboratory conditions, which may differ from how animals digest food in real farm environments
The Bottom Line
Farmers can use this research to support species-appropriate feeding strategies that work with each animal’s natural digestive design rather than against it. Moderate confidence: Feed formulations should account for the different digestive structures and timing in chickens versus pigs, even when targeting similar nutrient outcomes. This research suggests that one-size-fits-all feeding approaches may be less efficient than species-specific strategies
Livestock farmers, animal nutritionists, and feed manufacturers should pay attention to these findings. Veterinarians working with poultry and swine operations can use this information to explain digestive differences to farmers. This research is primarily relevant to people involved in animal agriculture rather than consumers making food choices
Changes to feeding practices based on this research would show benefits over weeks to months as animals grow more efficiently on species-appropriate diets. Immediate effects would be subtle, but cumulative improvements in feed efficiency and animal health would become apparent over a full production cycle
Frequently Asked Questions
Do chickens and pigs digest grain differently?
Yes, chickens and pigs use different digestive structures and timing to break down grain. Chickens have larger front digestive tracts and longer small intestines relative to body size, but both species achieve similar starch digestion levels from the same grain-based food.
Can you feed chickens and pigs the same diet?
While chickens and pigs can digest identical grain-based diets with similar efficiency, their different digestive structures suggest that species-specific feed formulations may optimize nutrition and growth. Research shows both species achieve comparable starch digestion despite different physiological mechanisms.
Why do chickens have longer small intestines than pigs?
The study found chickens have longer small intestines relative to body weight, but the research doesn’t explain why this evolved. This structural difference appears to be part of how chickens’ digestive systems adapted, though it doesn’t prevent them from digesting grain as effectively as pigs.
What does starch digestion kinetics mean?
Starch digestion kinetics refers to the speed and location where starch gets broken down in the digestive system. Chickens and pigs have different kinetics, meaning food moves through their digestive tracts at different rates and gets processed in different locations, even though final digestion is similar.
Want to Apply This Research?
- For farmers using a livestock management app, track feed conversion efficiency (pounds of feed per pound of weight gain) separately for chickens versus pigs to see if species-specific feeding strategies improve outcomes compared to uniform feeding approaches
- Farmers can adjust their feed formulation strategy by consulting with a nutritionist to create chicken-specific and pig-specific diets rather than using identical formulations, then monitor growth rates and feed costs to measure the impact
- Establish a baseline of current feed efficiency metrics for each species, implement species-specific feeding adjustments, and track weekly weight gain, feed consumption, and overall health indicators over a full production cycle to measure improvement
This research compares digestive function in young chickens and pigs under controlled laboratory conditions. Results may not apply to older animals, different feed types, or farm environments. Farmers should consult with animal nutritionists or veterinarians before making significant changes to feeding practices. This research is intended for agricultural professionals and does not provide medical advice for human nutrition or health.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.