She is definitely way behind on development. If i were you, at this point, i would feed her some boiled egg yolks, as much as she'll eat for a couple of days and then back off to twice a week and see if this helps her. The nutrition is really good for her and super easy for her system to absorb, so if she's having some digestive problems, it should hopefully bypass all that. I say this in addition to making sure she is on a good starter or even a game bird grower. She needs some supplementation to get her jump started.
But there is definitely hope. I have a girl who was kind of a runt - way behind in development for many weeks, but now she has caught up, and i am even hopeful that she'll start laying eggs one day very soon. She's very strong, so as long as she's eating and exercising, there's still hope.