Volunteers at the All About Animals Adoption Center on Riverside Drive near Central City Park say the shelter was broken into sometime before 8 a.m. Thursday morning.
They say pens were found unlocked, and that mostly "bully breeds" like pitbulls and bulldogs were let out and fighting, leading three dogs to be killed, and 8 others injured and sent to the vet.
Volunteer Lacey Templeton says she estimates whoever broke in caused around a few thousand dollars worth of damage.
She says around 25 of their 65 dogs were let out of their pens.
She says in the past, people have left unwanted pets tied to the gate , but this is first time someone has broken in and let dogs loose. The incident has them concerned about security.
No one called the police but a police officer stopped by and issued a report, took a statement and categorized the incident as "criminal trespass."
The Macon Police Department says they are investigating the case, and no charges have been filed.
Follow 13WMAZ's Tom George on Twitter @thetomgeorge