At the risk of driving people away from the idea of owning a larger pokémon to begin with, it’s not going to be easy, no. For one thing, housing tends to be difficult. Many apartment buildings don’t allow pokémon outside of their poké balls at all, or there may be very strict rules on what you can and can’t own. If you don’t live in an apartment, in some regions, the size of available housing may be restrictive as well. City housing in Johto, for example, is typically cramped and barely large enough to fit a group of humans and smaller pokémon, so larger pokémon may be confined to a small garden in the back of the house, if at all.

With that in mind, as sad as it may be to force your pokémon into their balls for most hours of the day, their poké balls will likely be vital. Luckily, a pokémon doesn’t need to be released and fed regularly, as modern poké balls can keep them in stasis for long periods of time, which means you may only need to take them out once a day. However, that once a day is a must, and it would be a good idea to plan on at least two hours daily for exercising and generally caring for your team. Parks are often set up for exactly this purpose, and they’re great places to meet other trainers who might also be facing the same struggles in caring for their pokémon (which in turn means you may have access to resources such as pokémon sitters, who can take your pokémon out while you’re at work or school).

If your pokémon is more noivern-sized than, say, onix-sized, you might still be able to keep your pokémon at home, depending on the size of your space, the diligence in your training, and your creativity with interior design. It’s not exactly an ideal solution (noivern especially require ample amounts of space to spread their wings … if you’ll forgive the pun), but you may be able to make do with a large enough loft-style apartment, if you avoid decorating your home with, say, tall floor lamps or wall decorations. Alternatively, balconies are wonderful places to let flying-type pokémon roost or come and go as they please, but be warned: some species of flying-types may be disruptive to the local ecosystem. Only give your flying-types the balcony if they’re well-trained enough to come back at the end of the day (or night) and to avoid unnecessary hunting and flying. Noivern and other dragon-types may be intelligent enough to be taught this. Fearow, mandibuzz, and certain other larger birds might not, and either way (although these aren’t flying-types), never give a balcony to a larger feline pokémon. Feline pokémon should be kept indoors as much as possible (or within their poké balls, in the cases of larger cats, such as pyroar and incineroar), as felines will hunt and decimate wild pokémon populations if left to their own devices outdoors.

One final tip: water. As tempting as this may be, do thorough research before allowing your water-type to swim in a lake or river running through your city. Some waterways are more polluted than others, so they may be ill-suited to pokémon that aren’t partially poison, ghost, or magikarp. Ponds in parks tend to be cleaner, and as tempting as this may be, use these bodies of water and not your bathtub. A bathtub is not a suitable replacement for adequate water sources when it comes to water-types.

In short, it’s difficult, but quite honestly, the biggest challenge is where to keep them. Space is your biggest finite resource in a city, and unfortunately, space tends to be vital for a pokémon’s physical and mental health. Once you figure out that part of the puzzle, the rest should be pretty standard from there on out.

Best of luck!