You find or make a Raven template
(Here's a workable one, although I would add the mimicry skill.) and buy one as an Ally. It's a Perk for most PCs. (Might even be a Dependent). A whole bunch of ravens is an Ally Group, again probably pretty low cost. If they're special ravens (e.g. they can talk in the sense of having a conversation and reporting back what they've seen, or are able to distinguish "get the key" from "get the gem" instead of just bringing back whatever's shiny, or things linke that, then the template will have a higher IQ or lose Mute or etc )