Making a new zombie type

Hi Peoples,

i'm relativly new to modding i have grasped the basics but i'm struggling with a couple of things

which xml files would i need to alter to make other animal's react like the Zombie dog 

i.e i would like to make a zombie Chicken and or Stag.

while leaving the origional animals untouched

any info would be Mush Appreciated.

 

[BFT2020]

Entityclasses

 

[c1appy.]

Entityclasses

i've tried to add to the EntityClasses file but with no success

i have got it where if you go onto the debug it's listed in the Zombie spawn menu but it will not spawn

and i get a red message on the CM saying the instance is not linked to an object.

if anyone knows of a tutorial i could view it would be a bonus

thx again