If they are coming inside the house there is something they want, they will go for even the smallest bit of food so check the dog food and look all around the kitchen including around / under / inside the cooker, microwave, toaster, pantry. Look in the back of cupboards especially if there is one on an outside wall that might have a pipe coming through it.

I'm not at all suggesting you keep a dirty house but like I say they will go for any bit of forgotten food or crumbs or blob of grease.

You can get various gels and ant traps to distribute around the kitchen. I normally blob some of the gel stuff around where the sink drain goes through the wall and keep an eye out for them coming in and do the same there.