First of all, the anklet is the symbol of the birdhouse where parrots are born. Parrot anklets in regular farms have specific numbers and records, which can be found, thus minimizing the risk of loss. However, this kind of anklet is a closed anklet, which can only be easily worn when the chicken's claws are soft.
Moreover, a parrot with a closed anklet also means that it is a domesticated bird. Many countries, even states, use closed anklets to identify domestic birds in order to crack down on illegal wild bird trade.
There is also an openable anklet, which is open. This is specially designed for adult birds. Eight-shaped ring, U-shaped ring, etc. Can be connected with a chain to control the parrot to move within a certain range. Many zoos use some "open" anklets to identify their birds. For example, a male bird wears it on his right foot; Women wear it on their left foot. In Europe, many zoos even use colored plastic anklets, which can also identify the sex and age of birds.