I feed raw. Kibble is way too expensive with 40 ferrets lol
Weekly balance is easier than daily. I suggest going back to Holistic Ferrets & reading back up on raw feeding. The percentages relate to their weekly dietary needs. I'll use my diet to example (keeping in mind, my ferrets require a higher bone content of 15%)
Monday: ground red meat, beef hearts, liver & kidney
Tuesday: chicken carcasses
Wednesday: Chicken carcasses
Thursday: ground red meat, beef hearts, liver & kidney
Friday: Chicken carcasses
Saturday: Chicken carcasses.
Sunday: whole prey (birds, rabbits, etc)
Always good to work out a staple food that you can get easily & cheaply (mine is chicken carcasses), then add on top your necessary components (hearts, liver & other organs; eg kidney), then add in more variety.