Well, it's not only the food, it's mostly being attacked by a moose or a dog or a bear whenever you leave your house. They aren't insurmountably hard but you'll be seeing if not fighting them constantly.
I had found a stone wall house with a pool on the outskirts of town and moved into it. Zombies were no worry as I cleared out the surrounding area, but animals kept breaking in. I had to break any glass walls myself and raid the town for furniture to disassemble to build wooden walls and boarded up windows, solely to keep out animals both normal and zombified. It would have been nice if I could have just killed all the annoying things. I like that it made me fortify but they weren't really dangerous.
I'd rather see something like the thread title, a horde of zombies very rarely migrating through an area if there needs to be a threat to keep static spawn users from being too safe once they clear out the immediate area. Preferably of a size that I'd likely want to hide from it, as that would give a good reason to have a fortified hideout that you quietly cower inside while listening to zombies go past outside. It would be cool if you could deplete this horde, so it would be less of a threat if you kill a lot of them. I think it would be more fun than it being a form of mobile non-static spawn. Maybe there could be a new type of zombie to lead them around, or for the horde to consist of. Perhaps you could see the horde on the map if you have line of sight to them, perhaps through climbing a tower or other high point. That would allow you to see the direction they are headed and if they get close, you hear them coming before the leading edge is in sight, so they can be avoided or hidden from with relative ease considering it would be a great many of them coming your way.