Throughout the seventh book in particular, the Death Eaters spend a *considerable* amount of time and effort developing inside men in all kinds of areas through the Imperius Curse (various individuals in the Ministry), intimidation/fear (Peter Pettigrew in the Order of the Phoenix), and coercing people to cooperate (e.g. by kidnapping Luna Lovegood to force Xenophilius Lovegood's cooperation).

Dumbledore, of course, took time to develop inside sources

> 
>  Most notably, Severus Snape
> 
> 
> 

but the Order wasn't aware of them. (I suppose that's why they're called *Confidential* Informants).

That being the case, why didn't the Order develop more inside sources? It seems like several of the more disgruntled Death Eaters (e.g. the Malfoys) may have been willing to flip voluntarily (or they could've been coerced to with the Imperius Curse).

Why didn't they do that?

**Edit:** I'm not so much asking about a current Order member trying to join the Death Eaters as a mole; I'm more asking about the Order compromising someone who's *already* a Death Eater through some means (e.g. Finding someone who's disgruntled, coercing someone, or using the Imperius Curse).