Model is not rendering after upgrading the project from Unity 5.0.3 to Unity 5.3.4

I had a project which was in unity 5.0.3. The project contains many models. Last week I upgraded the project to Unity 5.3.4. Now I am unable to see some models. Actually, the model is in the hierarchy. But cannot see on the game/scene . The problem occurs only for some models which have Skinned Mesh. Thanks in Advance