The desired simulation distance is ignored over the forced 32 chunk simulation distance. Using this machine, I tested from 6 chunks away whether or not the chicken was hopping up and down, and it only did from at least 6 chunks away with bobby enabled. This is highly unintuitive and confused me as a skyblock player, (although I guess I don't really need bobby in skyblock but that's besides the point) and I did not find anything in the config file or on the mod page suggesting this change in behavior so I'm reporting it as a bug.

Mod version 5.2.3+mc1.21
Fabric version 0.15.11-1.21