Risky business in Georgia's wild birds: contact rates between wild birds and backyard chickens is influenced by supplemental feed

Abstract

Backyard chickens are increasingly popular, and their husbandry varies widely. How backyard chickens are housed may influence the accessibility of chicken feed and water to wild birds, and thus, the contact rates between both groups. Increased contacts have implications for pathogen transmission; for instance, Newcastle disease virus or avian influenza virus may be transmitted to and from backyard chickens from contaminated water or feed. Given this potentially increased pathogen risk to wild birds and backyard chickens, we examined which wild bird species are likely to encounter backyard chickens and their resources. We performed a supplemental feeding experiment followed by observations at three sites associated with backyard chickens in North Georgia, USA. At each site, we identified the species of wild birds that: (a) shared habitat with the chickens, (b) had a higher frequency of detection relative to other species and (c) encountered the coops. We identified 14 wild bird species that entered the coops to consume supplemental feed and were considered high-risk for pathogen transmission. Our results provide evidence that contact between wild birds and backyard chickens is frequent and more common than previously believed, which has crucial epidemiological implications for wildlife managers and backyard chicken owners.

Virulent Newcastle disease virus genotypes V.3, VII.2, and XIII.1.1 and their coinfections with infectious bronchitis viruses and other avian pathogens in backyard chickens in Tanzania

“…Like in many developing countries, the main challenge to backyard chicken production in Tanzania is infectious diseases, of which NDV has the greatest impact by causing abnormally high mortalities in unvaccinated flocks ( 33 , 71 ). The high mobility of these flocks during their daily scavenging for food, and their interactions with neighboring village poultry flocks and wild bird species could significantly contribute to the viral persistence and transmission as has been recently demonstrated ( 72 ). Furthermore, Tanzania is not any different from other sub-Saharan Africa countries where disease surveillance, diagnostics and vaccination of rural poultry are the exception rather than the rule; most farmers sell off their flocks in their neighborhoods, or use ineffective traditional methods at the onset of clinical disease signs, and some of them may be unaware of vaccination as a disease control option due to constrained veterinary extension services ( 37 ).…”

Salmonella enterica frequency in backyard chickens in Vermont and biosecurity knowledge and practices of owners

“…In addition to determining how to reformulate biosecurity messaging to be more persuasive, the biosecurity risk of bird feeders adjacent to domestic poultry should be included in future messaging. While the uptick in Salmonellosis in Vermont backyard birds may or may not be related to the songbird outbreak of 2021 ( 39 ), a recent study in Georgia found that wild birds frequent chicken coops where there is accessible chicken feed ( 40 ). Northern Cardinals, a species commonly affected by S. enterica outbreaks, spent the most time around chicken coops, which demonstrates a strong potential for spillover infections into backyard poultry ( 40 , 41 ).…”

“…While the uptick in Salmonellosis in Vermont backyard birds may or may not be related to the songbird outbreak of 2021 ( 39 ), a recent study in Georgia found that wild birds frequent chicken coops where there is accessible chicken feed ( 40 ). Northern Cardinals, a species commonly affected by S. enterica outbreaks, spent the most time around chicken coops, which demonstrates a strong potential for spillover infections into backyard poultry ( 40 , 41 ). Further, a study in Canada found that 10% of all European Starlings and House Sparrows collected near broiler houses were positive for S. enterica ( 42 ).…”

Birds affected by a 2021 avian mortality event are strongly associated with supplemental feeding and ground foraging behaviors

“…However, the practice of supplemental feeding often generates complex ecological trade-offs among the avian communities that utilize provisioned foods [23,31]. For instance, supplemental feeding can augment individual physiological robustness, immune function, feather growth, overall fitness, and survival, especially during periods of food scarcity, adverse conditions (e.g., cold weather), and increased energy demand (e.g., breeding, migration) [23,26,[32][33][34][35][36][37].…”

“…On the other hand, supplemental feeding may also promote pathogen and parasite transmission by inflating the number of contacts between susceptible and infectious individuals [11,26,31,37,38]. Supplemental feeding has been reported not only to influence avian health, but also the abundance, distribution, and composition of local avian communities [32,39].…”