aside from price, you might find the boneless thighs in a good amount of grocery stores, but would be hard pressed to find yourself boneless turkey or duck thighs anywhere.
so what do i do? i bone out my own thighs, and it is EXTREMLY easy to do. there is only ONE bone in a thigh, and its strait as an arrow, pokes out at both ends and only takes a few cuts to remove.
i used turkey thighs for this demo because A.) i already had them and B.) they are bigger, so you can get a better look at what i am doing
gently pull the flesh back while working in and around the bone. be careful at either end of the thigh at there is cartalegse around the bone caps that you want to be sure to remove.
work the knife down both sides of the bone until only the flesh underneath remains attached hold the bone up off the cutting board so the weight of the flesh pulls the meat down. cut the hanging meat free from the bone and work up and down toward the bone caps. be sure to cut wide to avoid any small loose pieces.