For disinfecting cages and toys and other things birds use, bleach is likely the most popular choice. Bleach has a reputation for being an excellent disinfectant, and it’s very effective against both bacteria and viruses.
However, there are significant downsides to using bleach as well as equally effective alternatives.
Birds and inhaled toxins
You’ve heard of expression “canary in the coal mine”? Maybe you didn’t know it’s a real thing!
Well into the 20th century, coal miners brought canaries into coal mines as an early-warning signal for toxic gases, primarily carbon monoxide. The birds, being more sensitive, would become sick before the miners, who would then have a chance to escape or put on protective respirators.Sentinel species—Wikipedia
There is at least one modern study that suggests the same thing.
Birds are ubiquitously distributed in essentially all of the environments inhabited by humans; thus, if we understood the effects of a broad range of inhaled environmental contaminants (gas and particulate) on a wide variety of avian species, they could serve as highly effective and sensitive monitors of air quality.