Crevicetool is Right:
Those are poultry shears; they were used for disjointing roast fowl of all types - chicken, duck, goose, etc.
When I was in the housewares biz and taught cooking (several eons ago), I would sell a pair of these occasionally. The customer was always someone elderly, who had grown up with them.
They are very powerful and will go through the joints on a bird with ease.