Which condition is treated with chelating agents in birds?

The correct choice is lead poisoning, which is a condition that can severely affect birds. Chelating agents are specific compounds that bind to metal ions, helping to remove toxic substances from the body. In the case of lead poisoning, these agents work by binding to lead in the bloodstream, facilitating its excretion from the body, rather than allowing it to accumulate in tissues where it can cause significant harm.

Other conditions mentioned, such as dehydration, broken feathers, and preventing feather mites, do not require chelation as a treatment method. Dehydration is typically treated with fluids, broken feathers may involve careful grooming or feather regrowth support, and issues with feather mites generally need topical insecticides or anti-parasitic treatments. Thus, lead poisoning is uniquely associated with the need for chelating agents due to the toxic nature of lead and its effects on avian health.