Additionally, the whole herd and noise issue means easy interdiction
Send a group at least a few miles away as a roving patrol...find group of walkers...shoot walkers.
If you pick a point beyond gunfire range, you will draw any herds away from your position. Since it seems like they kinda keep going straight, interdict two groups, one say 2-3 miles out, then one 4-5 miles out. Any walkers hearing the gunfire will by definition have their bearings changed away from your base.
Repeat periodically (say once a day) to ensnare more.
Better yet, find a natural choke point (river or pass), create a trap-fence to temporarily hold them And command detonated mines...seed with noise makers on a timer (fireworks, explosives, etc) to draw them in, return periodically to detonate, mop up remaining, and re-set trap.
River or small swampy area would be perfect, as we have seen that mud works damn well.
Which brings up another point, since the farm obviously has decent water supply (it's a FARM), no need for a moat, just a soaker-hose and strip the turf from a perimeter, dig a shallow trench, line with plastic to prevent water loss, refill with dirt, add water...mud trap.
Also, they don't even put up tangle-foot wire? Given the lack of coordination or good vision in the walkers...it seems like a quick, effective, and easy way to gain some time on a herd attack to engage.
Hell, they don't even do that in the comic!
Again, total reliance on counter-PERSON defenses, rather than counter-zombie...
