Antibiotic-Free Poultry Farming: A Global Context
Intensive poultry farming has used antibiotic growth promoters (AGPs) since the 1940s and 50s to improve feed conversion.
ANIMAL PRODUCTION
8/27/20257 min read
Intensive poultry farming has used antibiotic growth promoters (AGPs) since the 1940s and 50s to improve feed conversion. By 1969, the Swann Report recommended banning antibiotics of human importance as AGPs (1). Between 1986 and 2006, Europe gradually prohibited AGPs (Sweden in 1986; avoparcin in 1997; the full EU ban in 2006) (1). South Korea, Chile, and Turkey also implemented similar restrictions (2). The withdrawal of AGPs was driven by the precautionary principle (the theoretical risk of disseminating resistance from the farm to the human population) (3).
Sub-therapeutic Use and Antimicrobial Resistance
The routine use of sub-therapeutic doses of antibiotics in poultry affects the intestinal microbiota, eliminates sensitive bacteria, and selects for resistant strains (4). The WHO and OIE warn that the misuse of antibiotics in animals accelerates antimicrobial resistance (AMR), threatening public health (5, 6). In some countries, nearly 70–80% of medically important antibiotics are used in animal production (7, 8). Global studies confirm a strong correlation between the use of antimicrobials in livestock production and the increase in AMR in human and animal pathogens (5, 9). The WHO concludes that restricting antibiotics in poultry production reduces the prevalence of resistant bacteria by up to 39% (10). Therefore, it recommends avoiding any prophylactic or growth-promoting use in healthy animals and reserving critical antibiotics for humans (11, 12).
Global Regulations and Prohibitions
In response to AMR, Europe leads with strict prohibitions: in 2006, it banned all AGPs (1, 13). The US FDA undertook similar measures in 2012–17: it directed the gradual elimination of growth-promoting antibiotics and, since 2017, established the Veterinary Feed Directive, which reclassified all important antibiotics to veterinary prescription status, eliminating their "for growth" use (14, 15). In Latin America, several countries have followed suit. For example, Brazil banned tylosin, lincomycin, and tiamulin (important for humans) as AGPs in 2020 (16), in accordance with the joint WHO/OIE/FAO position to eliminate critical antibiotics as growth promoters (17). Likewise, several countries in the Americas have restricted or banned colistin in animals, a human last-resort antibiotic (18, 19). In Asia, China announced strict regulations for 2020, prohibiting multiple AGPs (including colistin) and strengthening residue control (20). In summary, the global trend is to reduce or eliminate AGPs and regulate critical antibiotics (classified by the WHO) to preserve their efficacy in human medicine (6, 12).
Production Challenges Without Antibiotics
Eliminating AGPs poses health challenges, especially during critical phases. During startup (newly hatched chicks), there is a high health risk: young birds rely on innate immunity and a balanced microbiota that is still developing (21, 22). Modern production identifies the initial and final phases of the cycle as critical points where disease is vertically transmitted (from breeders to chicks) (23). In these stages, the absence of prophylactic antibiotics can increase early mortality and enteric problems.
Heat stress aggravates these issues. Excessive heat is known to dysregulate the immune system and digestion, reducing growth. In fact, the only long-lasting chemical coccidiostat, nicarbazin, cannot be used in very hot climates due to adverse interactions with thermal stress (24). Thus, in summer or at high thermal densities, the control of parasites and enteric bacteria becomes even more complicated.
Without antibiotics, coccidiosis and necrotic enteritis (NE) are critical threats. Lesions caused by Eimeria strongly predispose birds to outbreaks of NE from Clostridium perfringens (25). When ionophore anticoccidials and AGPs are suspended, cases of coccidiosis and NE increase, worsening the feed conversion ratio and mortality (25, 26). For example, one study reported that suspending antibiotic or coccidiostat treatments significantly increased clinical and subclinical outbreaks of necrotic enteritis (26). Controlling these diseases today requires rotations of vaccines and chemicals, more rigorous management systems, and alternative additives, as without them, antibiotic-free animals suffer weight loss and poor intestinal health.
Viable Technical Alternatives
To compensate for the withdrawal of antibiotics, multiple integrated strategies are available. Probiotics and synbiotics (live bacteria administered in water or feed, e.g., Bacillus) strengthen the intestinal microbiota (27). Prebiotics (fermentable oligosaccharides like MOS, FOS, XOS) stimulate beneficial bacteria (28). Organic acids (butyric, formic, propionic acid, etc.) maintain the intestinal barrier and reduce pathogens (29). Digestive enzymes (phytases, xylanases, proteases) optimize digestion and reduce substrates for harmful bacteria (30). Phytogenics (plant extracts and essential oils) provide antimicrobial, anti-inflammatory, and antioxidant properties to the feed. Toxin binders (to neutralize mycotoxins) and ammonia-chelating agents (to improve litter conditions) are also used.
Additionally, specific vaccines are fundamental: live or inactivated vaccines against coccidiosis prevent the parasite; and vaccination programs for breeders against Salmonella drastically reduce chick contamination (31). At the same time, biosecurity and environmental management are reinforced: moderate stocking densities, adequate ventilation, exhaustive cleaning, and pathogen-free water are key requirements (32). Precision nutrition (phase-formulated diets, digestible amino acids, adjusted protein levels, use of whole grains, electrolyte balance, etc.) completes the approach, as well-nourished birds are better equipped to face health challenges.
Together, these tools form a comprehensive package. There is no "magic wand": experience shows that it is necessary to combine several of these strategies to maintain intestinal health. In Mexico, for example, successful antibiotic-free farms used live vaccines against coccidiosis, probiotics, prebiotics, organic acids, and essential oils, along with strict biosecurity, achieving better performance and lower mortality than conventional farms (33).
Successful Cases and Evidence of Impact
In several countries, there have been examples of mass production without antibiotics. In the United States, major poultry companies have adopted "Raised Without Antibiotics" (RWA) lines. Perdue Farms—the fourth-largest national producer—labeled its RWA chicken in 2007 and in 2016 announced the elimination of all antibiotics except for curative treatments (applied to only 3% of their birds) (15). Tyson Foods followed in 2017 with a similar policy, eliminating the routine use of even ionophores (34). As a result, the share of RWA chicken has grown significantly in recent years.
In health terms, recent studies show that good management can compensate for the absence of antibiotics. For example, a comparative analysis in Italy found that well-managed antibiotic-free batches did not show worse health than conventional ones; in fact, the antibiotic-free chickens had a lower incidence of lesions like plantar ulcers and an even lower death rate (2.34% vs. 2.50%) (35). These studies suggest that, when accompanied by welfare practices (litter management, ventilation, immunization, resistant genetics), antibiotic-free flocks can achieve similar health standards to traditional ones.
Economically, the balance is mixed. Several studies agree that antibiotic-free rearing involves higher production costs—in some cases estimated at an additional 15–20% (36)—due to the intensive use of alternative inputs and lower densities. However, these costs have been partially offset by price premiums in premium consumer markets and savings in pharmacological formulations. Furthermore, corporate experiences indicate that productivity (daily gain, conversion) can be maintained at competitive levels with the appropriate health package. In summary, the health evidence shows technical viability, and the economic evidence suggests that the higher initial costs can be covered by a market price/premium (15, 36).
Challenges in Low-Biosecurity Environments
In countries with a basic level of management and limited biosecurity, the antibiotic-free transition is especially challenging. The PAHO/OIE/FAO warn that the excessive or inadequate use of antimicrobials in agriculture without professional supervision accelerates AMR on low-resource farms (6). In these regions, the availability of high-level alternatives is scarce and avian diseases circulate more freely.
As Latin American experts point out, the technological change implies health risks and additional costs that the local industry fears it cannot absorb (37). In exporting countries (e.g., Brazil), progress toward antibiotic-free production has been guided by the demands of external markets, but in most of the region, the poultry sector still uses AGPs responsibly (respecting withdrawal periods) due to a lack of internal demand and the priority of keeping production costs low (37). In short, in environments with limited biosecurity and resources, eliminating antibiotics requires significant investments in infrastructure, training, and access to alternative technologies; otherwise, the health and economic risk can be prohibitive.
Conclusion: A Trend or an Inevitable Evolution?
The technical evaluation indicates that antibiotic-free poultry farming is more than a passing trend. It is supported by a convergence of health evidence and international policies. Organizations like the WHO, FAO, and OIE insist that reducing the use of antibiotics in animals—especially those critical for human medicine—is urgent to preserve public health (5, 38). This premise has inspired global regulations (EU bans, FDA policies, colistin alerts) and a strong market push (consumers willing to pay more for "antibiotic-free" products) (13, 15).
Technically, experiments and commercial experiences show that with proper management, it is possible to raise birds without antibiotics while maintaining flock health (33, 35). However, the transition has a cost and poses new challenges (biosecurity, nutrition, enteric diseases) that must be addressed. Overall, everything points to this shift in poultry production not being merely a market trend, but a necessary evolution. It responds to the evidence that the traditional livestock model needs to adapt to face the antimicrobial resistance crisis under the "One Health" approach, balancing economic sustainability and health security (38, 39).
References: Scientific studies and reports from the FAO, OIE, WHO, and specialized entities (1, 4, 5, 6, 15, 16, 24, 26, 27, 33, 35, 37) support the points made.
(1, 3) aviagen.com
(2, 4, 20) La última chance de los antibióticos como promotores de crecimiento - aviNews, la revista global de avicultura
https://avinews.com/el-ultimo-chance-de-los-antibioticos-como-promotores-de-crecimiento/
(5, 7, 10, 11, 12, 13, 38) Dejemos de administrar antibióticos a animales sanos para prevenir la propagación de la resistencia a los antimicrobianos
(6, 18, 19) ¿Por qué la región de las Américas avanza hacia la prohibición y restricción del uso de colistina en producción animal? - OPS/OMS | Organización Panamericana de la Salud
(8, 9) A Review of Antimicrobial Resistance in Poultry Farming within Low-Resource Settings - PMC
https://pmc.ncbi.nlm.nih.gov/articles/PMC7460429/
(14) Timeline of FDA Action on Antimicrobial Resistance | FDA
(15, 34) The Market for Chicken Raised Without Antibiotics, 2012-17
https://ers.usda.gov/sites/default/files/_laserfiche/publications/102187/EIB-224.pdf
(16, 17) Brasil prohíbe el uso de antibióticos como promotores del crecimiento - Noticias - 3tres3 LATAM, la página del Cerdo
(21, 22, 23, 26) Producir aves de corral sin antibióticos: ¡Es perfectamente posible!
https://avinews.com/producir-aves-de-corral-sin-antibioticos-es-perfectamente-posible/
(24, 25, 32, 36) Desafíos en la producción de pollo libre de antibióticos: salud intestinal - El Sitio Avicola
(27, 28, 29, 30, 31, 33) Alternativas a antibióticos promotores del crecimiento en avicultura
https://avinews.com/alternativas-a-antibioticos-promotores-del-crecimiento-en-avicultura/
(35) Animal Welfare Assessment in Antibiotic-Free and Conventional Broiler Chicken - PMC
https://pmc.ncbi.nlm.nih.gov/articles/PMC8532607/
(37, 39) Desafíos del reemplazo de los antibióticos promotores del crecimiento -
https://avinews.com/desafios-del-reemplazo-de-los-antibioticos-promotores-del-crecimiento/
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