Worry or am I overreacting? 8 week Silkie chick recently sleeping a lot and not as active, loose dro

[Treysure]

Hi all - I'm in need of advice or a reality check. I have an 8 week buff Silkie who recovered from cocci a few weeks ago. She Recovered with antibiotics and has been very healthy and active until today. I noticed she slept most of the day, even while standing up. Her droppings are a little loose, but it has been 100f here for over a week. She is eating and drinking fine, crop seems normal, clear vent, no mites or lice, and she has been dewormed. She is also the smallest of the 8 in our flock. I put ACV in their water, food is dusted with DE, and in addition to her regular feed she gets plain yogurt, wheat grass clippings and fruit, veggies. I add tumeric and organic kelp to the feed. All the birds free range all day and she is always slurping up earthworms. But she is not gaining weight as fast as the others.
Tonight she ran to me for mealy worms and watermelon.

Naturally, little Poppy is my favourite. So is this something I should worry about; and if yes , any suggestions? Or am I driving myself nuts over this chick??!! Please help me get out of my miserable worried state. Thanks!

Update: this morning Poppy's droppings are very small but normal color and consistency. She ate a little yogurt mash w garlic and honey mixed in. And she gulped down a few blueberrys. I looked her over very well. She is thin with sharp protruding breastbone, but no other symptoms except the lack of a hearty appetite and excessive sleepiness.

Any one have some advice? Should I let nature take its course? Please help..