Found then on the bottom of my haive
We split it about mouth a go… queen is there but she don’t laying yet… 20191015_151551|281x500
Chalk brood mummies. The nights have still been cold. I’d guess that you didn’t leave enough bees on the brood to keep it warm, which along with possibly not reducing the entrance enough would lead to chilled brood, which leads to chalk brood.
If you split a month ago, your new queen, assuming the split made their own should be underway with laying. If not, give them a frame of brood. Remove the frames that are badly affected with chalk brood.
It is chalk brood and that can happen after doing a split or moving a hive, both of which causees stress to the colony, as well as a sudden change in temperature or a cold draft in the hive as @JeffH has explained.
The colony will survive but it takes time to recover and in the mean time cleat out the mummies on the cor-flute and when you do brood inspections even pick out mummies from the cells. I would progressively remove the frames that are more infected and render it down for the wax but definitely don’t use those frames in another hive as that will just infect another hive with the spores.
Cheers