I get some interesting questions sometimes. This is one of those:
My wife's family lives in Thailand and lose a lot of rice to rats,mice n the fields and storage sheds. They set traps and actually eat the FAT Rice feed Rats.
Question do Rat Terrier's do OK in the heat ?
Its not always hot in North East Thailand but April to August is hot and Humid but afternoon rains and place to get shade are abundant.
How much would a Rat Terrier with a little experience co$t ?
Maybe a 1-2 year old that knows how to hunt ?
And do they bring back the Rat to owner or rip it a part or try to eat ? Reason is they (Thais) really eat them but a Rat gnawed/half eaten on by a dog may not be acceptable... I know it sounds funny...;)
My answer, for what it's worth:
For your purposes, I think the age-old Thai rat traps, which use a spring pole and a noose snare are going to be cheaper, less trouble, and result in less cultural push-back.
Dogs are expensive to feed, tend to chew up the rats, and are not as efficient as a trap which is patient, cheap, and works in the dark.
The age-old spring-noose rat trap also works on squirrels, and you can use a tin can or bit of PVC for the barrel.
I make no judgement about eating rat. These are field and jungle rats, and are not eating garbage. Are they really that different than squirrel or rabbit?