At her age, she's way too young for the diet she's getting. The grains are diluting the vitamins in the food.
Until five to five and a half months (or her comb starts to redden and/or grow if she's for sure a pullet), she should be eating grower ration. Less than 5% of her total diet should be any grains, treats, etc.
Scratch is more of a treat designed to get them to 'scratch' around in the bedding. It's not a feed. It's mainly comprised of milo, a cheap ingredient. The other ingredients are usually cracked cork and wheat, but in small amounts.
Corn is VERY low protein (8-9% this year), and wheat is about 9. If you want to feed grains to supplement her and give her body condition, try wheat, cracked corn, and whole oats with lots of granite grit available. You can give her a pinch of sunflower seed meat as well.
I think her beak is showing her lack of nutrition. To boost her for now and correct this condition I would give her a week of Enfamilly baby vitamins (Polyvisol without iron, that formula is found at CVS and other pharmacies - not usually in the store.) Two drops in the beak daily for a week, then twice that week, then once the following week.
** THis is very important**
Vitamin A deficiencies start as little things like this, then they lead to bigger issues like respiratory and eye disorders, even paralysis.
In the mean time, grower or at least starter/grower please.
This is a very important time to her. You're not only seeing external development going wrong, there's also going to be internal development going wrong - like her reproductive organs - if not given enough "fuel" to make the perfect body. When that happens, that's when you see a lot of hens that have troubles laying later. The foundation you lay is the foundation for the hen's health for the rest of her life.
"In the old days" the food you're feeding would have been sufficient because they had other things they gave to the birds to make the diet sufficient, and they wouldn't have fed scratch but other grains. People still have scratch stuck in their minds, but in the wrong context when thinking about feeding birds. It's a mistake many (including myself) have made. So learn from my mistakes, and my following years of learning about nutrition and how it effects their growth.
That way I can save you the heartache I experienced.
If you do the vitamins, the feed change, save the scratch for bribes, absolutely fresh clean water. Then start to introduce the layer, oyster shell, etc at 5 months, your bird will still have time to correct itself and grow into a healthy, effective layer.
Please let me know if I can be of any further assistance. I'd especially like to know, if you follow my directions as given, the results. That sort of feedback is very important to me. Thank you.