This bug i think is working in minecraft 16w39c snapshot. This bug is when there is a block in the top of the chicken, the chicken will take damage. not like previews snapshot, The chicken not taking damage in one block on the top of the chicken. Hope YOU UNDERSTAND.
Environment
OS: Windows 8 (ver 6.2, arch x86)
Java: 1.8.0_25 (by Oracle Corporation)
Launcher: Minecraft Launcher 1.6.61 (bootstrap 100)
Minecraft: 16w39a (updated Wed Sep 28 05:33:50 GMT-08:00 2016)
Dupe of MC-50367