Scientists studied the tiny fungi living in chicken guts to understand how they change over time and how different feed additives affect them. They tracked 320 baby chickens for three weeks, looking at samples from their droppings to see what fungi were present. The research found that as chickens aged, their fungal communities naturally shifted and became more diverse, similar to how human gut bacteria change as we grow. Interestingly, special feed additives like probiotics and essential oils had less impact on fungal communities than the chickens’ natural aging process. This study helps farmers and scientists better understand chicken gut health by looking at both fungi and bacteria together, rather than studying them separately.
The Quick Take
- What they studied: How fungi living in chicken guts change as the birds grow older, and whether different types of feed additives (like probiotics and essential oils) change these fungal communities
- Who participated: 320 one-day-old baby chickens (Cobb 500 breed) that were raised for 21 days in cages. The chickens were divided into four groups that each received different types of feed: regular feed, feed with antibiotics, feed with essential oils, or feed with probiotics
- Key finding: The fungal communities in chicken guts naturally changed and became more diverse as the chickens aged from day 1 to day 21. Early on, a fungus called Candida dominated, but by day 21, other fungi like Fusarium and Malassezia became more common. Feed additives had surprisingly little effect on these changes
- What it means for you: If you raise chickens or work in poultry farming, this suggests that a chicken’s age is more important than special feed additives when it comes to developing a healthy gut fungal community. However, this is early research on chickens specifically, so more studies are needed before making major changes to feeding practices
The Research Details
Researchers divided 320 baby chickens into four equal groups of 80 chickens each. Each group received different feed: one group got regular feed, one got feed with an antibiotic called bacitracin, one got feed with essential oils (oregano, rosemary, and red pepper), and one got feed with a probiotic (a beneficial bacteria called Bacillus subtilis). The chickens were raised for 21 days, and scientists collected samples from their droppings on day 1, day 10, and day 21. They used advanced genetic testing (called shotgun metagenomic sequencing) to identify exactly which fungi were present in each sample and how abundant they were. This allowed them to track how the fungal communities changed over time and between different feed groups.
This research approach is important because it looks at fungi and bacteria together as an interconnected system, rather than studying them separately. The gut is like a tiny ecosystem where different microorganisms interact with each other. By tracking changes over time in the same chickens, researchers could see natural patterns of how these communities develop. This ’ecological perspective’ helps us understand that gut health isn’t just about adding beneficial microbes—it’s about how all the different microbes work together and change naturally as the animal grows.
This study has several strengths: it used a large number of chickens (320), tracked them over time at multiple points, used advanced genetic testing to identify microorganisms accurately, and tested multiple feed additives. However, the study only lasted 21 days (the early life of chickens), so we don’t know if these patterns continue as chickens mature. The study focused only on chickens, so results may not apply to other animals. The researchers used proper scientific methods with random assignment of chickens to groups, which strengthens the reliability of the findings.
What the Results Show
The main discovery was that chicken gut fungi naturally change dramatically as the birds age, regardless of what they’re fed. On day 1, the fungal community was dominated by a fungus called Candida albicans. By day 21, the community had shifted significantly, with Candida becoming less common and other fungi like Fusarium and Malassezia becoming more prevalent. The overall diversity and variety of fungi increased over time, meaning more different types of fungi were present by day 21 compared to day 1. This age-driven change happened in all four feed groups, suggesting that the chicken’s natural development is the primary driver of these fungal changes. The researchers also found that fungi and bacteria in the gut don’t exist independently—they interact with each other. For example, Candida was often found together with certain bacteria like Streptococcus and E. coli, but was rarely found alongside beneficial bacteria like Bifidobacterium.
While the feed additives (antibiotics, essential oils, and probiotics) didn’t significantly change the overall diversity of fungi, they did appear to cause subtle differences in which specific fungi were present at different times. The antibiotic treatment showed some different patterns compared to the other groups, which makes sense since antibiotics can affect microbial communities. The probiotic and essential oil treatments showed some unique clustering patterns, suggesting they may have had small effects that weren’t captured by the main diversity measurements. The researchers also identified that different treatments showed different metabolic features—meaning the microbes in each group were performing slightly different chemical functions in the gut.
This study adds important new information because most previous research on chicken gut health focused only on bacteria, largely ignoring fungi. While fungi are less abundant than bacteria in the gut, they appear to play important roles in the ecosystem. This research shows that fungi follow predictable patterns of change as chickens age, similar to what scientists have observed in human infant gut development. The finding that feed additives have limited effects on fungal communities is somewhat surprising and suggests that previous studies focusing only on bacterial changes may have missed important parts of the story. The strong connection between fungi and bacteria (called cross-kingdom correlation) highlights why scientists need to study both together rather than separately.
This study has several important limitations to keep in mind. First, it only tracked chickens for 21 days—the very early part of their lives—so we don’t know if these patterns continue as chickens grow older. Second, the study only looked at fungi in droppings, not in the actual gut tissue, so it may not capture the complete picture of what’s happening inside. Third, the study was done in controlled laboratory conditions with specific chicken breeds, so results might be different on real farms with different conditions. Fourth, while the researchers identified which fungi were present, they didn’t fully understand what functions these fungi perform or why certain fungi are beneficial or harmful. Finally, the sample size of 320 chickens, while large, was divided into four groups, which means each group had only 80 chickens—a moderate size for detecting treatment effects.
The Bottom Line
Based on this research, poultry farmers should understand that a chicken’s natural age-related development is the primary factor shaping gut fungal health, not feed additives. While probiotics and essential oils are popular feed additives, this study suggests they have limited impact on fungal communities in young chickens. However, this doesn’t mean feed additives are useless—they may affect bacterial communities or other aspects of health not measured in this study. The recommendation is to view gut health as a complex, multi-kingdom ecosystem that develops naturally over time. More research is needed before making major changes to feeding practices based on these findings. Confidence level: Moderate—this is solid research, but it’s limited to young chickens in controlled settings.
This research is most relevant to poultry farmers, veterinarians who work with chickens, and companies that produce feed additives for chickens. Scientists studying gut health in animals should also pay attention to these findings. If you raise backyard chickens, this information may be interesting but probably won’t change your daily practices. This research is specific to chickens and may not apply to other animals like pigs, cattle, or humans. People interested in probiotics or essential oils for their own health should not assume these findings apply to humans—chicken guts are very different from human guts.
If a farmer were to implement changes based on this research, they would need to observe chickens over several weeks to see effects, since the major changes in fungal communities happen gradually over the first three weeks of life. Any benefits from improved gut health would likely take 2-3 weeks to become apparent in terms of chicken growth or health markers. However, since this study suggests feed additives have limited effects on fungal communities, don’t expect dramatic changes from adding probiotics or essential oils—any benefits would likely be modest and gradual.
Want to Apply This Research?
- For poultry farmers using a health tracking app: Record daily observations of chicken health indicators (feed consumption, weight gain, activity level, and droppings appearance) from day 1 to day 21 of the flock’s life. Compare these observations across different feed types to see if there are practical differences in chicken performance, even if fungal communities appear similar.
- If using a farm management app: Set reminders to collect and observe droppings samples at key time points (day 1, day 10, and day 21) to track visible changes in gut health. Document which feed additives are being used and note any correlations with chicken performance metrics. This creates a practical record of what works best for your specific farm conditions.
- Implement a long-term tracking system that monitors chicken health outcomes (growth rate, feed efficiency, disease resistance) across different feed treatments over multiple flocks. Since this research shows that age is the primary driver of fungal changes, track how chickens perform at different ages rather than expecting immediate changes from feed additives. Use the app to identify patterns over time that may not be obvious in individual flocks.
This research describes findings from a controlled study on young chickens and should not be interpreted as medical or veterinary advice. The study was conducted in laboratory conditions with specific chicken breeds and may not apply to all poultry farming situations. Before making changes to chicken feed or management practices, consult with a veterinarian or poultry nutrition specialist who understands your specific farm conditions. This research focuses on fungal communities in chickens and does not apply to human health or nutrition. While the study provides valuable scientific insights, individual results may vary based on farm conditions, chicken breeds, feed quality, and management practices. Always follow established biosecurity and animal welfare guidelines when raising poultry.