Young bird seems uninterested in food

[MokiYoki]

So, around 3 weeks ago I noticed she was emaciated. So I brought her inside and started her on a diet of high protein soft food. At first I had to force feed her but after the first day she begun eating on her own and once she regained some weight and strength I brought her back outside where I happily watched her eating well with the others. Now she is falling back into the same issue. She doesnt seem to want to eat. She will peck lightly but she never swallows anything and her crop is empty. Other than that everything seems to be normal, her breathing sounds clear and everything feels fine. Her bowl movements seemed perfectly normal as well.
Does anyone know what this might be?

 

[Wyorp Rock]

So, around 3 weeks ago I noticed she was emaciated. So I brought her inside and started her on a diet of high protein soft food. At first I had to force feed her but after the first day she begun eating on her own and once she regained some weight and strength I brought her back outside where I happily watched her eating well with the others. Now she is falling back into the same issue. She doesnt seem to want to eat. She will peck lightly but she never swallows anything and her crop is empty. Other than that everything seems to be normal, her breathing sounds clear and everything feels fine. Her bowl movements seemed perfectly normal as well.
Does anyone know what this might be?

Can you post some photos of her and the poop?
What do you feed (type of feed and protein%)?

Have you looked inside her beak for any yellow/white plaques, lesions or sores? Any sour or bad odor coming from her beak?

 

[MokiYoki]

Her crop is full in this picture because I have just finished force feeding her after double checking that her crop was clear of any obstructions.

She eats a combination of "Show Bird Breeder MP" with 17% protein and "Red Hen Chick Starter" which is antibiotic free that has 23% protein. Its in seperate feeders so its free choice (this is how I stopped all feather eating in my flock over night). Also the coop door is open for free ranging from 10am till dark on more land than they have covered yet. So they forage as well.
There is a lot of natural rocky grit outside but there is also a bowl of grit by the door of the coop along with cuddlefish bones for calcium. (Not that she is old enough to lay)
Her breath smells absolutely fine and her crop is empty most of the day except for when she drinks water, and the inside of her mouth looks totally normal with nothing weird. Anything yellow or white would really stand out since her mouth is a blackish pink.
She hatched some time after the 20th of April so she is about 10 weeks old.

 

[coach723]

I'm not sure that what is going on now is the same thing that was going on at 3 weeks. I would treat for coccidiosis. Common symptoms are lethargy, sitting fluffed up, not eating or drinking, bloody or mucousy or runny droppings. Your dropping looks mucousy to me with some intestinal lining. Treatment is Amprolium, not sure what products are available in Australia, found this one:
https://www.backyardchickencoops.com.au/products/amprolium-200-for-coccidiosis-prevention-treatment

 

[MokiYoki]

I'm not sure that what is going on now is the same thing that was going on at 3 weeks. I would treat for coccidiosis. Common symptoms are lethargy, sitting fluffed up, not eating or drinking, bloody or mucousy or runny droppings. Your dropping looks mucousy to me with some intestinal lining. Treatment is Amprolium, not sure what products are available in Australia, found this one:
https://www.backyardchickencoops.com.au/products/amprolium-200-for-coccidiosis-prevention-treatment

I'm not sure that is the case as her food 3 weeks ago was still the medicated sort that protects against coccidiosis. Any second guess as to why? Also she became much better and put on lots of weight on her own after i started forcing her to eat for 4 days. Which doesn't seem like it would be coccidiosis either.
I'm ordering that medication anyways, always best to keep a well stocked medical cabinet!

 

[Wyorp Rock]

I'm not sure that what is going on now is the same thing that was going on at 3 weeks. I would treat for coccidiosis. Common symptoms are lethargy, sitting fluffed up, not eating or drinking, bloody or mucousy or runny droppings. Your dropping looks mucousy to me with some intestinal lining. Treatment is Amprolium, not sure what products are available in Australia, found this one:
https://www.backyardchickencoops.com.au/products/amprolium-200-for-coccidiosis-prevention-treatment

I agree with @coach723 I would treat for Coccidiosis as well.

 

[coach723]

Medicated feed contains a very low 'preventative dose' of amprolium. Outbreaks still happen and then you have to medicate with the medication which is a much higher dose.