Peachguy mentioned pet bedding,
as did you,Also would cedar or pine shavings that is used for pet bedding work as a brown?
sorry if I misinterpreted.Cedar shaving would be great for pet bedding as they are high in lignin and have a low pH would slows their decay and therefore the nitrogenous compounds in your pets fecal matter will not emit negative smells as much due to the fact that they will be tied up by bacteria and fungi that are very slowly decomposing the wood.
I have not done extensive reading on this subject but as I understand it the concern is not so much bacteria or fungi, but parasites. Our pets harbor parasites that also can infect us. Check out the link I provided above. The important thing is that we all stay safe.However, purely from my own knowledge; cats, dog, horse, cow and even human and so on all have bacteria in their manure and fungal spores are in abundance in the air. So, what would be interesting to look into would be: why are cat and dog manure (and human) so profaned against as far as disease is concerned?