I think this is not a bad idea and the only reason it would fail is if the owner is as condescending to his guests as he is in this text. I really do think there could be a market for a zoo which is tranquil and which gives the impression of being in nature though. I question the idea of the visitors feeding the deer while they are in the enclosure for the same reasons people above have already stated (overfeeding and possible attacks) but if you could make them friendly enough to be a subject of good pictures and give people the feeling of walking almost in the flock itself I think that would be a good exhibit. Feeding the birds in a controlled manner would be a better idea I think.
If the aim is a tranquil and beautiful place I would go for one enclosure with deer and and one more landscaped and garden/park-like with birds of different kinds. If you want to make children part of your clientele a further idea could be to have an old-fashioned farm with heritage breeds as a third leg. Most children like being able to pet a sheep or cow or to see the pigs play in the mud and grandparents would probably like taking them somewhere that looked like an old-fashioned farm and give them lessons about how milk, cheese and butter is made and so on.