good point on picking thru for what they like best...Blessedacre!
Never seen that recipe before, certainly a nice range of ingredients.Your buying a bucket for each part right? So 20 buckets? Using only half of some? (Kelp, DE and peanuts) I calculate that would be only just over 2 big barrels. (55gal barrels/drums I believe you call them in the US?) Checking grain weight and knowing some of these things are heavier than others I'll work on roughly 400 pounds per barrel.
Rounding down to 800 pounds:
1/4 pound per bird per day = 320 days for 10 birds or 213 days for 15 birds (likely amount for much of the year) or
1/3 pound per bird per day = 240 days for 10 birds or 160 days for 15 birds. (likely amount for cold winter weather)
Commercial products will say 1 pound will feed 5 birds but that's calculated for light crossbred layers. Obviously the more they can free range or you can supplement the less grain they will need. Dorkings are great free rangers and love to get out and find their own dinner if they can.
I don't mix my own as getting high enough protein is an issue. I haven't calculated the protein in that mix but my gut tells me it will be lower than I prefer. If they are free ranging and catching their own bugs and getting egg as well that will help to increase the protein %. The thing to remember with that is when you have heaps of eggs and bugs it's great but over winter your likely to have neither of those things if you live in a cold climate. You may want to increase the protein feeds in winter to make up for that.
Oh and don't assume there will be no waste with a whole grain diet. I tried feeding mine whole grains and the stinkers used to only eat the ones they preferred and flick the rest out onto the floor for the mice to get.Now they are back on pellets till I find another option.
Good luck with your new adventure into chicken keeping!
gave me another idea too. check with a local feed mill. they can run the numbers and tell you what the ratios would be for that mix. and also might be able to mill it all together for you and formulate a pelleted feed the birds can't pick thru. i'll see if i can find my feed formulation program. been a while since i used it. but it'd give me the info about that diet.