a winter concern about ants

[goertzen29]

I know there are all sorts of topics on ants and on winter but I'm wondering about the combination.  I noticed today that there are some ants moving about my hives maybe a dozen.  I live in Nebraska so winter is basically upon us, but I'm wondering if these few ants will create a problem with my honey stores.    Do ants ever take up residence inside a strong hive? Do I need to open up and inspect or just assume that since I see the ants outside the hives they live outside and will eventually stop entering the hive as it continues to get colder. 

I need a little reassurance, I was just surprised to see ants at all this late in the year.

thanks
Jay