If one finds an animal (of certain species) in or around Y'rushalayim [when the Beis Hamikdash is up and running] one can assume it was destined to be brought as a karban and give it to the custodians of the Beis Hamikdash materials to be offered as whichever karban suits it. (Sh'kalim 7:4)
Also, if one finds an animal in public there is a protocol to follow to decide initially if it is likely to have been lost - as opposed to being far away from but in the care of its owner - and then to determine whether and how its owner should be identified for the purpose of restoring the animal. (Baba M'tzi'a 2:9)
At what point does the assumption that the animal near Y'rushalayim is destined for service kick in vis-à-vis the protocol for returning lost animals in general?
- Is the latter forgone in favor of the former?
- Does the initial check for signs of ownership (e.g. being saddled, being fenced in, etc.) need to be surpassed before collecting it and shipping it up the hill to the mikdash?
- Does the second stage of attempting to find the owner and all that it entails have to transpire before this conclusion can be reached?
The commentaries on Sh'kalim mention the possibility of the owner appearing, but only in discussing the opinion of R' Y'huda and not the main rule in the mishna. So it's unlikely that this rule circumvents the general hashavas aveda ones. Maybe the owner's status only matters because R' Y'huda's case is that of the karban pesach, which needs to be tied to the correct owner for reasons unrelated to hashavas aveda?