What is the ruling on offering as a sacrifice a lost sheep whose owner is unknown?

Whoever finds a stray sheep is permitted to sacrifice it after noting its characteristics and type. He is obligated to announce it for a year in public places. If its owner comes, the finder must compensate him with its value at the time of the slaughter.

The finder can also eat it immediately and guarantee its value to its owner whenever he appears, or he can keep it and spend on it from his own money, then claim the expenses back from its owner, or he can sell it and keep its price.