The second flock was a group of escapees set free by the Flock from the Institute for Higher Living in The Angel Experiment. After Max killed Ari for the first time, she was informed by Angel that the escapees went on their own way. Their fates are unknown and they were only mentioned a few times after.
"Bird-Girl" is the only confirmed member of the second flock and implied to be the leader.
Possible members include the dozens of other experiments who were held at the School. Experiments who were mentioned specifically include:
- two small children with several vital organs such as "kidneys, bowels, a heart" located on the outside of their bodies. Max predicted that they didn't have long to live.
- a large cat resembling "a serval or a margay" with human eyes and human-like fingers beneath its retractable claws.
- a second winged child younger than Bird-Girl.
- Total was the only one from the Institute to stay with the Flock.