Honestly how hard could it be to make yukkuri countermeasures for a farm. You can basically just make a spike floor around your garden with stuff like broken ceramics and glass shards or something and it'll ward off most yu's. The few who can think of a way to get around it are probably patchoulis who if they're smart enough to build bridges or something are probably smart enough to not get involved with humans too.
Honestly how hard could it be to make yukkuri countermeasures for a farm.
We don't see protections against yukkuri for the same reason we don't (usually) see protections against birds City humans at least are excused as reinforcing whatever glass they have might be too expensive for them, but keeping birds away is pretty much the first thing a farmer should do after planting the seeds