Your best bet is to dig up the weeds. Crab grass is really easy to pop out. And, if they are big then, just put down some grass seed. If you keep your grass cut, you shouldn't get that much. IF you have to resort to chemicals on your lawn, ask your Vet what she thinks. If you ask the pet stores the salespeople won't know enough. If your neighbor's use a chem lawn service and there yard has a slope when it rains the residue of the chemicals they use will run off into your yard. Just a word to the wise.