Wtf? This is ridiculous. Who the fuck is going to be giving feral dogs a pill everyday? And why would you want a reversible contraceptive for feral dogs? You want a one-and-done irreversible one, which neutering is.
If it could be mixed into dog food it could be fairly easy to use. You'd just have to feed stray dogs for a decade or two and have the problem mostly solved. With added benefit of stray dogs being less of a nuisance if they are getting a bit domesticated by feeding them regularily.
Neutering is not possible in villages. You'd be hard pressed to find a vet anywhere nearby.
Usually this is done by people who visit the village and do it all at once.
So you think that it's more feasible to obtain thousands of pills and have someone give pills to stray dogs daily than it is to have a vet visit the village once?