Brain Teaser November 22

Your objective is to buy exactly 100 farm animals with exactly 100 dollars. You must buy at least 1 of each animal. You may need some paper!

The Costs:
Cows: $10 each
Pigs: $ 3 each
Chickens: $0.50 each

Hint:

There's a lot of chickens; over 85, but under 95.