Chucky won't shut up about the one he kept as a pet being eaten by the others. I think I'll shoot him, that sort of thing seems to impress these raider types.”— Ryan, Log Entry #87
Chucky was a member of the group of raiders in the Jury Street Metro station. Chucky was concerned about his tame mole rat being eaten by other attacking mole rats in the Jury Street tunnels. It is also implied that Chucky was killed by Brigg. 
Chucky is only mentioned in Fallout 3.