That mixture looks pretty OK. Only one category of ingredients that may be a little heavy is the fibre of 10% +.
I purchase a fairly generic scratch/layer feed from Pet Club for $9.99, but I do not use it for their exclusive alimentation. I like to make part of their feed myself.
I have some 5 gallon cans of wheat berries (grains) and some rolled oats, corn meal, and popcorn kernels that I place in my Bullet Blender, a handful at a time, and reduce the size of the kernels (my chickees are just 3 month old pullets). In addition to that I save all of the eggshells from the store bought eggs we eat and grind them to a powder in the Bullet Blender. The chicks really like these different tastes, though I haven't figured out how they determine taste.
They are large enough now that the rolled oats do not need to be ground down, and these oats are their favorite. Next to that they like the corn meal and cracked corn pellets. I still use the Pet Club scratch/layer feed mostly because it is so cheap. When they leave some of it in their feeding dish I just put it in the blender and grind to a powder -- placed with the other grains they eat it up very well in the powdered form.
It doesn't take much to make up a batch of customized feed if you have a small blender like my Bullet brand, and you will get some pride when you see how well they like the different grains. I have even dried earthworms out in the sun and put them with the egg shells in the blender to a powder. They REALLY like this, and just think of all the good animal-type protein they are getting.
So, to answer your question...the mix you have is OK nutritionally. The question is, "Do the chicks like the 'taste'? If not, try the blender trick and/or add some oatmeal or corn meal. Guaranteed to get them eating like hogs.
Because they are foraging they are sure to find crickets and grasshoppers, etc. which will give them the best nutritional support they could ever need, plus all the seeds from the pasture-type feed.
Edited by A V Davidson - 1/15/16 at 2:49pm