Josie,
Everything I have to say on the topic will only scare you more. Not because any of it is true, but because I like sayin' things that scare people. :-)
I'm assuming that the rats are under the house, and they chewed a hole to access the kitchen. This means there are so many down there that they needed more space. Think of them as fuzzy little pioneers moving westward for more land. They probably have guns, but that's a whole 'nother discussion.
I've tried placing signs that say "NO RATS ALLOWED" but the little buggers can't read. And even if they could, they are notoriously disobedient creatures.
And you can't ask for help because as soon as word gets out about the legion of rats living under your house, the health department will come and bulldoze your house.
The really scary thing is that if they can get in your kitchen... they can also get in the bedroom... and probably climb all over you while you sleep. I hear they are drawn by the sound of snoring, just so ya know.
They are almost certainly under the bed. Sorry, but they're rats. Rats have no sense of shame (much like me)
OK! This is maybe the Best Post Ever! Lines like "This means there are so many down there that they needed more space." and "probably climb all over you while you sleep" are still cracking me up!!!