Put the summary of the bug you're having here

What I expected to happen was...:
So, I made a Hardcore world and I went into an Oak and Birchwood forest, and found 2 wild wolves(This also happened in another Harcore world in the spruce forest). I made a house, killed some skeletons, and looked for the dogs, and to my dismay, couldn't find them, AT ALL. I searched ~150 block radius, and still couldn't find them. I was able to conclude that they despawned when it happened in the spruce forest
What actually happened was...:
I believe they despawned. No other wild animal despawns except for wolves(not even cats, to my knowledge), and it is a bit frustrating to know that wolves despawn in just a few minecraft days of finding them.

Steps to Reproduce:
1. Make a hardcore world(Snapshot 15w45a) with the seed number "1788632004"
2. Travel to the forest, which should be on a hill North of your spawnpoint
3. Survive for a few days. Cage the dogs if you must, sleeping is optional, I don't believe it makes a difference.
4. Don't watch over the dogs 24/7

I hope we can get this fixed ty very much