zombies pickup eggs

ok so i was on craetive mode and i spawn ed loads of chickens at night at then the zombies were picking up the eggs 

how to reproduce:

1. build a 4x4 room.

2. get a zombie spawn egg and a chicken spawn egg.

3. place the spawn eggs.

4. wait 5-10 minutes for chicken to lay an egg.

5. the zombie should have picked up the egg.