Poultry shears

Take it to a butcher ?

Sharp knife will do it.

ps I'm wrong, it's the hip joint of the bird.
The wing is attached to the shoulder joint.

ps it's the shoulder joint of the bird.

We used to have our own chickens, and other poultry.
To break off the leg from the rest of the body we found that you don't need a special tool.
Move the leg back and forth and feel for the flexible point. Then put in there the point of a sharp knife and cut through the tendons etc which are supporting the joint. You shouldn't need to cut through bone.
It's the same with a shoulder of lamb.

Being as Chicken and Turkey bones are prone to splintering rather than breaking cleanly, it’s probably much easier and quicker to cut through the wing and leg joints with a sharp knife, or snip down through the flesh to find the joint using Kitchen scissors!

Failing that, the supermarkets that portion up cooked Chickens from their Rotisserie counter, appear to do so using a stainless steel pair of Garden Secutors!

I watched a programme last night about festive cooking. The turkey breeder/cook was chatting about the pros and cons of a turkey crown. He removed the legs from a fresh turkey with a knife and made it look effortless. Presumably it must have been a very sharp knife.