Most feed company's labels list protein and other items as % min. This is generally a lowball # in most all cases. For example many bags of shelled corn will list the protein as 7% min. Many times the actual shelled corn in the bag will be 9.5% protein. This is because like hay, actual crop harvest conditions, field fertility, etc. contribute to the grains feed value. This is one of the reasons companys like purina change thier indgredients somewhat to keep the analysis on the feed label very close. Otherwise the bag of Country Acres 10% might actually be 14%. One local small feed mill got tested a few years ago by the state as to whether or not his feed in the bag matched the label and only 30% of his products matched the label!!!!!!!!!! A lot of small mills are like this, they use the protein out of a book for the label on for example, corn. The larger mills (Purina) test every load of ingredient that comes in and use it accordingly. If the shelled corn comes in at 9.5% protein, they may only need x pounds per 50lb bag, but if it comes in at 6.5% protein, they may need y pounds per 50lb bag. Thus sometimes the feed bag that changes its ingredients occasionally may actually be a more consistant feed than the feed bag that always has 20lbs of oats per bag.