What do the swallows symbolize in The Devil's Arithmetic?

In the book, swallows are mentioned seven times. The swallows fly around the death camps as the smoke rises from the ovens. This is actually a disturbing image, but it highlights an important fact: tragedy is as much a part of life as beauty is. So the swallows symbolize life in all its complexity.
In some cultures, swallows symbolize freedom, salvation, or even the souls of the dead. Certainly, these are meaningful interpretations and can be relevant to The Devil's Arithmetic.
First, let's discuss the swallows and their connection to the complexity of life. In the book, we read about swallows hunting insects while the smoke rises from the death camp ovens. The swallows are "raucous," focused only on catching their main meal of the day. They are oblivious to the suffering in the camps, and they have no knowledge of tragedy. While the birds fly freely in the sky, human beings are cruelly incarcerated and killed in horrific conditions on earth. This juxtaposition of freedom and enslavement highlights the complexity of life.
Interestingly, the ancient Egyptians associated swallows with the souls of the dead. In light of the death camps, this interpretation is ominously accurate. From the text, we read that it is the practice of the swallows to dip down in search of insects and then to soar back up above the barracks. The smoke from the ovens signifies that many innocents have been sacrificed to achieve Hitler's vision of Aryan perfection. Hence, the swallows also symbolize the souls of the dead.
In the book, Hannah concludes that this image of swallows flying freely is incongruous with the suffering that she sees. She thinks that the swallows should be "mourning by the smokestacks" instead. Yet after Hannah returns to her world, she notices that talk and laughter dips and soars like swallows at the dining table. Her observation again highlights the complexity of life, where death exists side by side with human existence. In her present life, there is freedom and hope. In the past, the one she has just come from, there was only death. Our memories consist of experiences that speak of both tragedy and hope. We must trust, as the swallows apparently do, that evil will never vanquish freedom.