No, you haven't stumbled onto our To Kill a Mockingbird character page (although it is worth checking out!). Macon Ravenwood has named his dog Boo Radley.
Boo Radley's name is a clever little joke. Macon is acknowledging his reputation as Gatlin's mysterious town shut-in (just like the original Boo Radley). Boo Radley the dog is his own mystery, though. He appears wolf-like at times, and like a sluggish, grizzled, old mongrel at others. The Sisters even talk about a wolf that Macon's dad had kept around.
Wait a second, just how old is Boo?
However old he is, this pup has got some pretty sharp eyes. Boo gives the phrase seeing-eye dog a whole new meaning—Macon can literally see through Boo's eyes. What Boo sees, Macon sees. That explains how Macon knows so much town gossip even though he never leaves the house.
Sharing eyesight can really connect you to a person, apparently. After Macon dies, we last see Boo following the rest of the family around, "whimpering like a lost pup" (2.12.12).