Legal Question in Landlord & Tenant Law in Oregon

It sounds like they did exactly that. In theory, you can file a motion under ORCP 21 D to force them to clarify their answer. You can also make requests for admission under ORCP 45. Or you can leave the pleadings alone and simply put on evidence at the hearing.

Which route makes good sense depends on the particulars of the litigation, the allegations, and the defenses, and the controversy. You mention that it's a landlord/tenant case, which are often relatively informal, quick, and there is less at controversy (hundreds to a few thousand dollars) compared to other civil litigation actions. Obviously, employing (or at least consulting with) your own attorney will be beneficial, if it's cost-effective and cost-feasible to do so.