Inside a box on the road near Ludgershall, Wiltshire, a passerby found the box of 51 pipistrelle bats - a protected breed - and all but two of them were pups.
After they were rescued they were taken to a nearby wildlife hospital where they were given round-the-clock treatment before being dispersed across Southern England to be cared for by volunteers.
It is thought that a builder may have come across the colony and rather than contacting authorities such as Natural England they removed them.
Marilyn Boyes-Kortis, from Wiltshire Wildlife Hospital, said: 'It is absolutely disgusting that someone could do this.
'It is cold at night and they would have died very quickly if someone hadn't found them. They must have been really cold and babies need warmth. Read More