It's hard to say if Dil and Ichy are abnormal for their species, since we don't really know much of their reputation among others, aside being predators. It is normal for crocodiles to hang out with birds, although these birds just clean the croc's teeth, not help them hunt.
Though there was that episode of the TV show with the bellydraggers, and they saw perfectly fine. Maybe Dil was born with a sight defect, or maybe she's just really old and can no longer hunt on her own. She would have become a burden to whatever group she belonged to, so they abandoned her. Then she met Ichy.
Why Ichy would work with her, I'm not sure. He's the only sharpbeak we ever see (feathered I mean), far as I know. So it's difficult to say if there's anything wrong with him. One idea I heard long ago is that maybe he forsaken his original diet (perhaps fish and insects) in favor of dinosaurs, which made him an outcast among his own kind.