Four fawns. One Mom?

The question is.. are these four fawns siblings, cousins, adopted or unrelated.

Although this is clearly not one of the better photos I've taken and posted it does have four fawns with one adult.

They were all grazing together at the back end of a field.

There was one other adult in the field but it was a least half a field away and didn't seem to have any association with the four fawns.

What do you think? Anyone know how common it would be for four fawns in one litter?