Can you get a regular picture of the bird so we can see location and pattern?
Sudden heaps of feathers would indicate a molt. As would a balding bird, assuming there were no signs of a struggle. It can be brought on by sudden lighting changes, dehydration, nutrient deficit, stress... any number of things, including that's just when it happened. Any recent changes?
Mind if I ask some diagnostic questions? What do you feed including treats and supplements? How many birds, in how much space? Are they all the same age? What breeds? What did you treat those lice with?
Molting is hard. High protein treats are a good choice during this time. Feathers are made of 90% protein and it's amino acids.
Hope she recovers quickly.
I would be miffed if I had a 10 month old molt... She shouldn't be laying eggs if she is molting. That's another sign... the whole reason I add young layers is for winter eggs.