Encounters are cool, and I like them and will give them some thought and see what I come up with. I would like for it to be a rule of thumb, however, for every bySwarm encounter to be overcome in at least two interesting ways. I added another option to this encounter as an example - or rather I would, if I could edit it.

My idea for an alternate way to overcome the encounter is if the PCs make a great Perception check, they find the eggs first, and by threatening the eggs, they can force the Owlbears to withdraw until they move away, at which point the Owlbears are concerned for their eggs and leave them alone.

If they destroy the eggs, however,the Owlbears fly into a rage, and will fight to the death (otherwise, they will try to flee if near death like any other creature).