Non-domesticated yukkuris that live in the wild (forests, mountains, countryside, farms, etc). For non-domesticated yus in the city, use gutter trash
Wild yukkuris, despite living in a more hostile enviroment, usually have better chance of survival compared to the gutter-trash or abandoned pet yukkuris due to the fact that most children are taught useful lessons from birth by their parents, such as: to how to use toilet outside their homes, how to avoid humans and other dangerous areas and creatures, rationing food during winter etc. It also helps that wild yukkuri generally encounter less humans than city strays.
The biggest benefit of living in the wild though is the fact that because a yukkuri's growth isn't hampered by humans, some yukkuri can grow into a dosuyukkuri which can massively boost the prosperity and survival chance of all nearby yukkuris (as long as the dosu isn't a dumbass shithead who uses her newfound strength to try to attack humans)
Still, as mentioned living in the wild is generally a more hostile environment. There's a larger amount of wild animals and predatory yukkuris. Also food is less abudant during winters and wild yukkuris need to stockpile food for hibernations and avoid breeding to avoid having more mouths to feed which is something a lot of yukkuris fail at. Most notably though shitheads tend to prosper more in the wild as there is no humans that they can get themselves killed with. It's not common for a few shithead yukkuris to completely wreck a prosperous wild yukkuri environment.
As such, most wild yukkuris tend to form clans to increase their survival rate.