My chick is not growing

[Champers11]

While she still doesn't seem to be getting any larger (she can literally walk under the others' legs), she is eating and pooping more regularly now. I found out yesterday that she probably had a full crop. It was most likely keeping her from getting all of the nutrients. I knew that their crops would be full after eating, I just didn't know that it should be empty and flat in the morning. I had another chick, the bottom left one in the first picture, that had a full crop that died yesterday. She was acting very lethargic, so I took her to a guy that raises rare chickens. When I got to his house, he rubbed on her crop and she threw up and had diarrhea at the same time. Within ten minutes she died. It was so terrible to watch. I hate learning about stuff the hard way. He told me that since I had been giving them grit, it may have just been something that could not have been helped. This morning I read in another post about applesauce and lactulose that a vet recommended. I guess next time I'll know.

I know this was a while ago, but how did your little chick go?? I have exactly the same challenge at the moment with one of my silkies, who is only half the size of the other chick, and at 17 days old, weighs the same as my other 7-day-old chicks.