Hay in our area is selling for $3.75-$5 and 40-$50 square and round bales respectively depending on the type of pasture. Three cuttings this year will work as long as we get some consistent rain during this next month or so.
Attached are a few websites that discuss feed mixtures with several options depending on cost/availability. Others may have information that they feel is more correct. Most seem to agree that Soybeans should be limited. I did not realize that there were so many soy options which can change the protein content as well as the cost. All seem to agree that they must be roasted, but there are a lot of websites that call into question the use of soy for animals or humans.
A few websites discuss that the high husk grains like oats and barley should be limited as well. The husked versions of oats are grown/available in our area. You might buy the "triple cleaned oats" or "Canadian oats" In the northern areas which is a different grain and probably easier on the digestion. Horse folks use this in our area, but are 3-4 times the price. Oats sprout well for winter use as a semi-green feed too.
The websites seem to disagree about the protein content of several of the grains as well.
http://www.lionsgrip.com/protein.htmlhttp://www.thepoultrysite.com/articles/94/feeding-chickens-for-best-health-and-performancehttp://www.gov.mb.ca/agriculture/livestock/poultry/bba01s20.html