Mobs suffocate / go through blocks when growing up near a solid block

The bug

Animals seem to suffocate when growing up near a solid block.

How to reproduce

1. Create a one block large, two block high enclosure. Use solid blocks like cobble.
2. Throw chicken eggs in it until 4 chickens have spawned
3. Wait until all chickens are grown up
4. Count the chicken

Most of the time all of the chickens have died, sometimes 1 or 2 survive. This happens not only in tight enclosure but also randomly near walls or blocks.
If the blocks are transparent (glass, fence) the animal just can walk through.

I think this is probably due to a smaller hitbox, that is immediately enlarged, when the animal grows up.

See this comment and ticket: https://bugs.mojang.com/browse/MC-1524?focusedCommentId=43968&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-43968

Also note DpP41Mf.png which provides a concrete way to reproduce and an explanation.

Code analysis

Code analysis by Xcom6000 can be found in this comment.