Here is what you do. It is not labor intensive. It still requires oven space, but no more than if you had to finish breasts.
Get a half breast, on the bone, and use a paring knife to cut a slot. Make a farce, use a piping bag and pipe it into the slot.
Finish it in the oven, pull the breast off the bone and plate.
In fact you don't even have to make a farce. Just pipe sausage into the pocket and it will be a nice surprise.