In feb this year one of my CKCS had to be speyed we have noticed since then she hardly ever self grooms ! she seems to have no idea what to do anymore she is 2 I have tried letting her lick a little honey from my fingers then applied a small amount to her back feathers but she didn't even sniff .....all she attracted was flies and had to be bathed asap
Other than keep her clean yourself you cannot do anything. Some dogs are just not as clean in their habits as others, and soem groom fastidiously (most of the Northern breeds seem to be like this).