I think it should be but it's not. I did receive this correction "Ese búho estuvo en esta granja un mes." I'm not sure why "por" would be incorrect, although it's entirely possible that there is something that I don't know. It also doesn't seem to like lechuza instead of búho.
As I understand ese refers to something close by (I think of it as being able to point to it), while aquel is more general.
Ese libro - that book that we can see
Aquel libro - that book that we are talking about
The word bank used Aquel on this, I would've said Ese, bc the context doesn't discern that it was "more removed" from the speaker. I'm confused about aquel and ese in this translation. Any help please?