As animated films go, this is certainly not my favorite but my two children and I agreed we enjoyed it. The animation is great, the characters are likeable and funny and the story kept us engaged. I can't think of anything I dislike about Free birds, it just doesn't have that wow factor which would make it really great.
I would give it 3.5 stars if I could as 3 stars seems a little harsh and 4 a bit generous, I would still recommend it to families with children under 10, it's a funny film and kids will definitely enjoy it.