This is the second bag I have ordered; my budgies love walking in it and chewing it, and the vet recommended they have some bird sand as well. I use newspaper to line the bottom of the cage (best for hygiene and for monitoring poops!), but I always keep a little sandbox with clean sand for them to play in and chew on. The fennel pieces smell fabulous, too.
I recently bought this product and I am delighted with it. It is so much better than sand as it keeps much cleaner. It smells pleasant too. Being heavier, it doesn't fly out the cage like sand. I have an indoor aviary with zebra finches who are always busy and they love to peck about in it picking out bits of shell. I shall be using this product in the future!