You are absolutely spot on ! This morning the mash had all disappeared. It seems to have gone down well, however the chick still has some dried poop underneath its vent (I think its not as much as yesterdays morning though, can you please take a look at both pics? )
The mash I made was by mixing their chick crumb with some yogurt and water to a sloppy consistency.
I am not sure what else I can try apart from the electrolytes in the water like you mentioned previously ?
I will try trimming the feathers further but I am afraid in case I cause damage. After I have cleaned I will apply oil like I did yesterday morning as well.
As you saw from my thread, it takes time and consistency.
Keep on cleaning and oiling and keep on feeding wet mash with a dab of yogurt.