I've read other threads and looked at the pics, what I have is definitely chalk brood.
It's in a hive that had been one of my strongest, so not sure how it happened. It's a deep with 2 mediums, no queen excluder.
When I went through the hive to find the queen, there were a lot of frames with chalk brood intermingled with capped and open brood.
What happens with the brood that appears to be ok? This hive has at least 10 frames of brood, no less than 1/4 in chalk brood form. I will go back next week and look for queen again, but wasn't sure of what I will do after that. Combine a nuk to it? I am going to raise some queens this spring, as soon as orange blossom flow is done and saw palmetto starts.