As a person that raises sheep I can say that they do provide more then just a food source...in fact my wife is spinning some of the wool as I am typing this. Also check out Genesis chapter four...the sheep were offered as an offering to God. So you would be assuming they ate the sheep based upon what we currently do, not based on what scripture states.
Offering what was considered valuable
4:4 And Abel, he also brought of the firstlings of his flock and of the fat thereof. And the LORD had respect unto Abel and to his offering: