Baby chick no longer growing

I have a 5 week old Buckeye chick that seems to have stopped growing. The other babies that I got at the same time as her are at least twice her size and have many more feathers than she does. She does eat and drink regularly and has normal, but small, poop, but just isn't growing anymore. She seems to lay around most of the time but she can and does walk around when she needs to. She is also a cryer, she cries and cries all the time unless someone is holding her. All the others seem to be up and active a lot of the time and they don't cry hardly at all anymore but she is definitely different. Does anyone know if there is something that I should be feeding her. I give all the babies Nutri-drench vitamins in their water, medicated grower crumble food, dried mealworms, and we've started giving them some hard-boiled or scrambled eggs, oatmeal and some other fresh food. I'm at a loss as to what else I should be doing to help her and I'm worried as the others get bigger she will be in harms way with them as they already step on her a lot since she's always laying around. Thank you for any help

Don't do the Nutri-drench all the time. The fat-soluble vitamins (A, D, E, K) can be over-supplemented leading to toxicities. Instead of vitamins, consider adding a straight probiotic to their water instead such as Probios powder to help them get the most nutrition out of their actual food.

Give her extra protein treats such as the egg, tofu, yogurt, etc. to give her some additional resources to draw from. Make sure everyone has chick-sized grit available for proper digestion of non-crumble foods.

I agree with the yogurt & tofu suggestion above. A local breeder also does whey protein sometimes too, for those chicks who are struggling a little. Are the other chicks the same breed, so that you can make a good comparison?