Given that everything is made of matter,and matter, once having existed, will always exis(albeit it can change form)-coupled with the belief in a some Christian standpoints that Animals do have a soul...
Here is my answer:
'If' there are three realms for matter to exist in: the positive realm, the negative realm and the neutral realm....
My guess would be animal matter would continue to exist in the neutral realm.
Why? Because they have niether merited or dismerited the positive (heaven.
They have certainly not merited the negative (Hell) because Animals have no concept of sin, and that is the only thing that could keep them from it.
The only place left, in my opinion would be the neutral realm (Limbo).
Linda L. Gens