finski! is that really you??
remember that chalkbrood is a fungus. you can help control it to some extent if you can make the environment unfavorable to fungal growth. good ventilation is one way. also keeping temps up in the hive rather than cooling the hive.
having had my own battles with chalkbrood, i would not combine. i would probably see if they make it through the winter then put them in new equipment with a new queen. they will still carry the fungus with them, but have a chance to get past it. the old equipment needs to be bleach dipped and left out in the sun to cook a bit. cut out the old foundation and melt it for wax. to late for that now, but when it warms in the later spring.
in the mean time, if you want to save them, feed the crap out of them but do it in a way that does not introduce moisture into the hive. no hive top feeder or baggie feeding. a jar feeder would probably be ok if not left on over night, but remote feeding would be better.