I've used grass mats for my cockatiel and agree they're great for foraging setups, but I'd add one caution the thread hasn't touched on: check how the mat is joined. Staples or wire edges can be a real hazard for birds that pick at seams, so I always look for woven or sewn edges instead. Also worth rotating mats out to dry fully between uses, since damp grass grows things you don't want near a bird. Curious what size others are using and whether anyone has found a source that's reliably untreated.