The weapons with STUN trait work with END parameters and since animals don't have specific END, we have to make up a system that would simulate them being stunned after losing their "END".
I propose - if an animal loses half of its Hits, it is susceptible to stun weapons as if they are on END = 0.
For example, a giant bear with 40 hits is shot several times reducing its hits to 25. Then someone hits her with stun baton for 8 dmg. The bear is then stunned for 3 rounds (25-8 = 17; 3 under 20)
I propose - if an animal loses half of its Hits, it is susceptible to stun weapons as if they are on END = 0.
For example, a giant bear with 40 hits is shot several times reducing its hits to 25. Then someone hits her with stun baton for 8 dmg. The bear is then stunned for 3 rounds (25-8 = 17; 3 under 20)