Consuming Their Own
Warning This Section Does Contain Spoilers
The Veridical Codex Umbra speaks of the Ritual of Cleromancy.
cleromancy - is a form of sortition, casting of lots, in which an outcome is determined by means that normally would be random, such as the rolling of dice, but are sometimes believed to reveal the will of God, or other supernatural entities.
The Raven uses this Ritual to decide who will be picked to be the Perfect Vessels. What is not clear is what is the result of the Perfect Vessel and what the Perfect Vessel's job is.
Abigail's son, Alexander, was chosen as a Perfect Vessel and she should have felt elated and proud, but instead she was anxious and ashamed of her feelings. Why would she feel that way? During the Sparrow Meditation they talk openly about consuming the Deer and eating its flesh, sharing it with fellow Family members. Is this representative of the Perfect Vessels? Are they sacrificed and consumed by fellow Family members and this is the reason for Abigail's anxiety? She is constantly remembering her son's Ritual of death or is constantly dreading what is to come?