worms?

I think Callie has worms! I've noticed she's losing a little weight, she's always been on the thin side, but shes getting thinner, but yet shes hungrier than usual. I think its worms because she regularly kills and shreds voles outside(eww)  What type of worms does this cause, and what is the best product treatment I can buy?  

Thanks

Honestly, I'd take her to the vet for treatment. Or at least call the vet about treatment. A lot of the OTC stuff can be ineffective or even dangerous.

She needs to be seen by the vet to do a fecal test.  Don't just give a med because you think that will take care of the problem.  Losing weight and still being hungry can also be a sign of thyroid problems.