This would hopefully not be your experience with them, maybe more of an example of how wrong deer farming could go. It's certainly a worst case scenario. A lot of people farm deer around here, and there's a lot of theft and pointless poaching, such as just killing the animals for the fun of it and leaving the meat, sometimes taking the antlers, often just massacring them because they're a pest. Once 70-odd deer were machine-gunned and dog-hounded into a dam on the farm I'm speaking of. (Yes, the machine gun is illegal in private hands here, but who listens to that? Law abiding folk, that's all).
My brother lives on a deer farm, and there's endless problems of every sort. The farm, which belongs to his landlord, runs fallow of four or five different but now mixed strains, as well as chital, reds, rusa, and a few other species of deer. The landlord doesn't manage their genetics, just lets them breed at will. The fallows are all chronically inbred, there's many spikers among all species there, and those with semi-correct antlers have badly misshapen forms and don't have symmetrical tine placement as well as missing most of their tines. The fallow include charcoal, spotless, beige/cream, white, and a few normals. There's a few cross-species hybrids too. The deer all routinely attack one another, including the stags killing and mutilating the does. They're all scarred terribly and the farm supports an enormous population of scavengers that have no need to hunt due to the constant presence of dead deer, from violence as well as lethal spiker genes. If they were mine I'd cull the lot, they're so bad genetically, never mind their attitudes.
The deer are meant to roam, so if you pen them they'll need a huge amount of land or supplementing. They're given stock licks and lucerne once they show signs of starving on this 'farm'. The stags can be some of the most dangerous livestock known to man, once they lose that wild fear of humans. They're a life-threatening animal to try to handle or manage in any way, and truly vicious, especially if cornered, but the stags will come running from acres away to try to kill you. There's almost nothing you can do to escape or intimidate them. They kill dogs and the goats on the property, and basically anything that they can. They go over and under the deer fencing if they can, to get you. This is regardless of gender and the time of season. They're mangy, scarred, wormy, incredibly aggressive, not handled or treated in any way at all except when guided into a truck to be sold to be butchered, and the way the landlord gets them into the truck is to offer himself as prey and escape through trick concealed doors in the tunnels. His son copped a deer's hoof through his lower jaw and into his skull, barely survived. If you look directly at them, they charge to attack, no matter the distance. A semi-tame deer is so much different to a wild deer. People say bottle-fed and hand-reared stags are the worst of all.
One other deer I was familiar with as a child was a doe of a quite small species, not sure which, but she went from a little girl's pet to a vicious unprovocated hoof-stabbing mauler who was not able to be handled and would bite like a dog. And on the other hand, there's a big professional deer farm not far from here, where they manage to hand-feed some of their deer, but still have issues with very aggressive stags and hence the sheer danger levels of managing the animals properly. Staff will die, it's just an occupational hazard.
In future I'd like to 'keep' deer, but since they're wild all over Australia, I wouldn't officially obtain any, I'd just go hunting for my meat. I've got a pretty good eye for phenotypical expression of defective genes, so I'd manage their genetics the good old fashioned land-steward's way... I'd eat those unfit to breed. Bugger farming them! There's also great demand for, and money in, crops of both animals and plants that don't threaten your life so consistently, as a rule. They're so much safer wild.