that was my thought. if it's that few, it's no big deal. keep track. chalkbrood is fungal and usually self limiting, but in some cases it can be bad. some people say ventilate, but there has been some written, and i found this true for me, that getting the heat up in the hive is better.
that means having only a small bottom entrance and no top opening. it might cause a lot of bearding if you are hot, but it seemed to do the trick for me in the past.
are you in a wet area, or has it been wet?
anyway, do a little research on chalkbrood and see if this fits.