Chickens spawned from a thrown egg have 5 hearts of health.

Put the summary of the bug you're having here
Chickens from a thrown egg have 5 hearts of health instead of 2.
What I expected to happen was...: Chicken would have 2 hearts.
Describe what you thought should happen here
Chicken should have died from a single stone sword hit.
What actually happened was...: Chicken had 5 hearts of health.
Describe what happened here
Chicken died from two hits of a stone sword.
Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here Throw eggs until a chicken spawns.
2. ... Try to kill it with any sword.
3. ... Chicken will die only when she takes 5 hearts of damage. (3 hits from a wooden and golden sword, 2 hits from the rest)