The world's smallest bird is the hummingbird.
In holding this title, hummingbirds are also in possession of the tiniest bird feet.
Apparently, it is a popular aviary myth that hummingbirds do not have feet at all. But as you can see, they do! Their proportionally long talons make them excellent perchers. BUT- their legs are so stubby that walking is not typical or indeed feasible.
Good thing they are wondrous fliers, and spend almost all their time in mind-boggling flight.