BRP If your Feeding a Layer formulation it should be sufficient.
You should not need the oyster shell, thats why layer mash/mix/crumbles is called layer, its got the calcium included.
Like Arrt said layers 16%.
If you want to reduce your cost you can mix your own, this page is pretty helpful for figuring your own formulation...
http://www.lionsgrip.com/protein.html
Just keep in mind Beans of any sort need to be cooked.
They have a enzyme that inhibits digestion and can even harm the digestive track.
I also Give my Birds a boost with Vitamin/electrolyte mix I get at TSC.
It only lists directions for 55 gallon batch but I figured about 20 grams to 5 gallons is close to the packages directions.
You could mix less and use more often, I give them that mix once per week though.
Here I could not just feed layer through the winter, got to feed some corn to keep them warm.
If your do mix your own with whole grains make sure they have grit , it will help them out a lot.
Mine are on a mostly corn regimen here and for what corn costs to layer,
they lay very well. Corns less the 9 a 100 weight and layers 18-20 for 40-50 lbs.
Once forage is under snow I will need to supplement them a bit more protien, for that I'll have the mill mix me some mash.
thinking maybe 13%... Just due to cost.
I got grower (22%) mixed in the spring , 500 pounds at 150.00 dollars or 30 a hundred, which saved me 70 bucks plus I have a tax exemption on file at the elevator which saved even more.
But back to point, the lower protien mix should bring me down closer to 100 dollar mark on 500, and if I take a 1/2 ton or ton I get a additional savings for volume.