RLCraft 2.9.3 | Tamed Cockatrices (Ice and Fire) Disappearing

I have a chicken farm, and when cockatrice spawn from the rotten eggs, I let them grow inside the house before letting them outside and setting them on patrol to protect the base (inside a small town). However, they keep disappearing after a while. There's no way they are all getting killed as I sleep everynight to protect my villagers right? Even nametagged ones are disappearing which makes me wonder if anyone knows how the patrol mechanic works in detail?