how often were mass graves used in the antietam area, specif...

how often were mass graves used in the antietam area, specifically whats known as pleasent valley in washington county md. and if they were used would they have been covered by rocks to keep out the wildlife?

Any mass graves where usually dug on the battlefield or very close to it. Bodies were often on the fields for days prior to burial & it would have been a very unpleasant job to move them far.Often they were sallow & temporary graves. Yes, many bodies were likely dug up by animals.