Do shavings and manure need to be seperated for composting?

After completing a number of site consultations and speaking to a lot of people in our horse community about composting, I have found that a number of people that are already composting are seperating their shavings from the manure prior to composting.
When I ask about why people are doing this, a common response is that they thought that shavings would not compost down.
Though it is true that shavings and sawdust do not compost as quickly as manure does, they will compost down eventually.
At my test site, I am able to compost shavings and manure down in as little as 3-4 weeks. The shavings are barely recognizable.
A common problem with composting with shavings is that the carbon to nitrogen ratio is not correct. As mentioned in our compost management guide, horse manure itself is the ideal ratio of 25:1, so as soon as you add shavings you throw the ratio off.
What this means is that if you are composting with shavings you will need to rebalance the C:N ratio by adding more nitrogen sources. The reason that it appears the shavings will not compost is that they can't because once all of the nitrogen is "used up" by the "bugs" in the pile, the breakdown of raw materials will slow and cease. Thereby giving the appearance that shavings don't compost.
By adding nitrogenous materials such as grass clippings into your pile/system, the composting process will fire up again and your shavings will continue to degrade.
My advice to those seperating shavings from manure is to save yourself the time and energy. Leave it all together and rebalance by adding nitrogenous materials!