In the vanilla game, there are about a dozen settlements in the Commonwealth with preexisting settlers occupying them, most of which lack the numbers to effectively combat a wasteland that is constantly trying to kill them. Finch Farm, for instance, is surrounded by super mutants, gunners, and the Forged, all of which could eliminate the family of four with little trouble. Even more egregious, perhaps, is Somerville Place, where we are expected to believe that a single father and his two young children are able to survive one of the most dangerous regions of the Commonwealth. All of this is immersion breaking, in my opinion, but this mod attempts to alleviate it by placing "disposable" settlers at select vanilla settlements to give the impression that they can hold their own against anything less than a concerted effort by a superior enemy.

Disposable Setters?
"Farmhands" are similar to common settlers, but you cannot trade with them, command them, move them, or assign them, and although they count toward a settlement's population, each brings his/her own food, water, and bed, so they won't be a drain on settlement resources. Furthermore, each "farmhand" brings 2 defense points to his/her settlement; however, they are mortal, as it is assumed that, over time, they will die off during attacks and that, as the settlement grows, their roster spots will be filled by regular settlers and other recruitable NPCs. Thus, the "disposable settlers" descriptor.

Update (v4): It seems that at higher difficulty levels, especially those introduced by mods, the Farmhands are getting steamrolled rather quickly, and in some instances, they're being killed before players even have a chance to claim the settlement (let alone increase the population and set up proper defenses). To combat this, I've given each Farmhand a health boost as well as a couple of stimpaks.

Farmhand Locations
"Farmhands" can be found at the following settlements in numbers ranging from two to four, depending on the settlement's size and perceived threat from its immediate environment:

Abernathy Farm: Three farmhands.
County Crossing: Three farmhands.
Finch Farm: Four farmhands.
Greentop Nursery: Three farmhands.
Nordhagen Beach: Three farmhands.
Oberland Station: Two farmhands.
Somerville Place: Four farmhands.
Tenpines Bluff: Two farmhands.

Compatibility
Every "farmhand" has its own unique base record, so this mod should be compatible with everything. If used in conjunction with the Settlement or AiO versions of my "We Have Names" series, the "farmhands" will function normally, but they will not have the names, height scaling, or expanded settler functions from those mods.