[cypher]

Hi & welcome to HC.
I wouldn't advise making your own mix unless you really understand ham nutrition & the nutrients in the various grains & seeds that are used, it's worth doing if you do understand all that or have the time to study it but not something to undertake lightly.
Barely is a really good grain for them & hard to replace but you could try some buckwheat if you can get hold of that, preferably whole but hulled would be ok if that's all you can get.
Protein is the easiest nutrient to supplement if your mix is low, mealworms or a little chicken will easily make that up.
Giving a small portion of ham safe fresh veg daily will also help a lot with micro nutrients & is probably better than giving supplements.