That sounds like an impossible amount of feed for a goat to consume. I won't claim any experience with feeding goats, but Dustin has one this year, it weighs 40# and eats 1# of feed a day and has been gaining 2-3# a week
Ours won't eat an ounce over 3.5% of body weight, is a very fussy eater and is still gaining, not like a lamb, but gaining