Rat Bedding and Ferret cages?

Okay about the rat bedding, why is the yellowish type of wood shavings is bad? im using right now this care fresh type, and i dont like the color of it because its a dull color. could you tell me wat is bad about it. and is there any other type of good bedding? And about the ferret cage, would the lenght between the wires be to big for rats? Im looking at the one that is on ferret.com and its the first cage on ferret nation cages. If you think that is not good enough please tell the right cage for them that is big,roomy,and perfect...thanks