Cut them in half

Genesis 15:9-10 - So the LORD said to him, "Bring me a heifer, a goat and a ram, each three years old, along with a dove and a young pigeon."

Abram brought all these to him, cut them in two and arranged the halves opposite each other; the birds, however, he did not cut in half.

I wonder if Abram did this all by himself. It seems like he did. I wonder what tools he used because it is no small task to cut an animal in half -- no matter which way you slice it.