I'm always amazed at folks who suggest using poison. It is indiscriminate and illegal.
The angle I would use would be rabies vaccinations. In Texas you are required by law to have your dogs and cats vaccinated against rabies. From the sounds of it those folks have a bunch of dogs that aren't up on their vaccinations.
On February 27, 2003, the Texas Board of Health approved amendments to Texas Administrative Code Ch. 169, Rabies Control and Eradication. The rabies vaccination schedule will still require that dogs and cats be
[ul][*]vaccinated against rabies by 4 months of age and[*]be given a booster one year after the initial vaccination. [/ul]
Following these first 2 vaccinations, dog & cats can be vaccinated at either 1-year or 3-year intervals, depending on the type of rabies vaccine used. Local ordinances may have more stringent requirements.
Not sure what the penalties are for not complying though.