Noticed since our servers moved from 1.16 to 1.17 that chickens are clipping through blocks compared to previous versions when attacked by a Fox. So anything that uses a fox to harvest chicken drops will fail as it will push the chickens outside of a contained space. Tested mainly with Glass Blocks, but occurring it looks also with other blocks.
Examples:
Fox attacking chickens in 1x1 or bigger blocked in container can cause chickens to clip through the blocks when attacked.
Easiest Replication: Have a fox in a 1x1 container with 1 or more chicken(s) spawn in the box to see that when a fox attacks a chicken it can cause it to clip through.
AC:
Chickens should not be clipping/pushed through walls/blocks of a container that has space for the entity.
Would MC-2025 happen to describe your issue? If not, please provide some screenshots and/or videos of this issue occurring whilst the F3 debug screen is enabled.