Disease transmission is the biggest concern with feeding wildlife. Artificially congregating wildlife through feeding alters natural foraging behavior causing changes in movement and distribution. The artificial competition from crowding at feed sites leads to increased fighting and injury.
Pennsylvania is facing Chronic Wasting Disease (CWD) in deer, and mange in bears. Both diseases were either absent or much less likely to be found a decade ago and both diseases are now escalating in Pennsylvania. Wildlife feeding brings animals into closer contact with one another and for longer periods of time than typical. Increased contact increases exposure.
Feeding sites harbor and concentrate disease agents deposited by infected animals creating a reservoir of disease. Healthy animals become infected by ingesting contaminated feces, eating contaminated feed or nearby vegetation, or in the case of mange and bears, by rubbing against contaminated surfaces where mites persist.
Wildlife feeding can increase transmission of CWD and mange. Infectious agents, like the CWD prion, can be shed in oral and respiratory droplets and other bodily secretions like urine and feces. CWD is always fatal to deer and elk. Mange, which is caused by mites on the surface of the skin, is highly contagious and a common cause of mortality in bears. These diseases impact wildlife populations by causing mortality or debilitating illness. Other diseases such as bovine tuberculosis, salmonellosis, toxoplasmosis, lungworms, and tapeworms can also be transmitted by feeding.
Risks for nontarget species. Items used to attract big game will draw squirrels, raccoons, opossums, rodents, skunks, and foxes, directly or indirectly. Many of these species are known carriers of transmissible disease, such as rabies, canine distemper, parvovirus, leptospirosis, Baylisascaris and ascarid roundworms, avian pox, and trichomoniasis, several of which have important human health implications.
Feeding blurs the lines between wild versus domestic and free-ranging versus private. Citizens who recreationally feed big game frequently assume a feeling of ownership over these animals. This violates the public trust doctrine that wildlife is a publicly owned resource. Wildlife associate food with humans resulting in habituation and wild animals become indifferent toward humans or human activity. This can lead to increases in vehicle strikes, property damage caused by wildlife, and other nuisance wildlife problems such as human-conditioned bears rummaging through trash or human injury from habituated wildlife getting too close. Some wildlife, like bears, can have home ranges that span 10 square miles or more. Habituation depreciates wildlife's natural independence from people, ultimately, "de-wilding" animals for human convenience.