I use this item for my companion animal, not my pet. I use sphagnum moss I usually get from the gardening store. I decided to try this product from Walmart. It smelled like fresh, dry hay when I opened it. I soaked it, and let it expand in order to separate it. If you plan to only use part of the block, cut it lengthwise, through the block.
because the cage I warm and moist, I noticed a weird smell, the next day. Not mold or rot. It was old dog food. The smell was quite unpleasant.
When fluffed up, the moss filled a 5 Gallon bucket, and more. It was a great product in all ways, except that unpleasant odor. I ended up using it in the garden.