The only thing that I don't like about the shavings is when the birds keep getting them into the water... I have been raising chickens for about 15 years now, I use either straw or shavings depending on how much room there is. If I am using a small brooder I use shavings, if they are in a larger area I use straw. Shredded paper should be fine (I think) since it isn't a slick flat surface.
I was just curious because I saw lots of pics here today of baby chicks standing on newspaper. I wouldn't use our local paper even if it was ok to keep them on newspaper, they use petroleum based ink. I won't even use it for my earth worms. Might not hurt anything, but I don't take chances.