The biggest, most significant thing left out of the cost of hay when figuring out what to charge is the quantity of nutrients within the hay itself. Quite often around here (Ohio) the value of the nutrients alone within the bale itself when figured based on the cost of fertilizer exceeds the cost of what the bale itself is being sold for in feed value. In other words, and these aren't accurate values but used for illustration purposes, say it costs $45.00 in fertilizer to produce a bale of hay (this is the value that hardly anyone takes time to calculate), and then the hay producer sells that bale to the cattle producer for $35.00, the bale producer didn't make a dime. Instead, it literally cost the bale producer $10.00 for that bale of hay, and that doesn't even factor in time for harvest, harvest fueling costs, wear and tear on haying equipment and delivery/travel distance costs. I'm glad you asked the question. Too many hay producers sell hay around here and don't realize that they are literally giving away the farm.
To get at a 'fertilizer value' for your hay, go to your extension agent and ask him to help you calculate it. It's not hard to do, but there are several figures you will need, and rough estimates are NOT what you want to use. Weigh several bales and get an average weight. Don't guess. Hay producers are typically lousy at guessing the weight of their bales, and don't measure the weight by the dimensions of the bale either. Density of hay bales can vary by as much as 2.5x from one producer to the next, equipment type, and separate cuttings. Ideally, get a hay analysis to find out the nutrient content of the hay. This is the ONE factor that if you don't have an exact measurement, you can use the values the agent has, although values having a difference of 15% or possibly a bit more would not surprise me. (15% is close compared to how far your other values could be off if you choose to use estimates.) You will also need the current value of fertilizer by component. From these values, you can calculate the value of the fertilizer that has gone into producing the hay being sold.
Be careful and just make sure you aren't inadvertently giving away the farm in the process of trying to make a profit off the hay sales.
