Several things against you. First, likely more than 65 million of years of natural selection for capacity to hunt other birds. Second, you may need to raise your guardian with chickens and based on limited experience I have the chickens might kill an eyas (nestling raptor) if they can, as they have some hardwired tendencies as well. Thirdly, you may have some disease exchange issues between bird species assuming first challenges are licked. Fourthly, I know of no raptors that would stay tight on such small location. Fifth, your raptor will be vulnerable to other raptors. Finally, legal issues already noted.
Still possible, remember wolves ---> dogs. I am sure wolves can be taught to leave poultry alone but roaming tendency would be a problem as with a trained raptor.
Human social rules in reality biggest obstacle.
