This is really cool. What you do is lead your pigs or cows to the water they go in get pushed into the lava there stuff gets cooked and then puts it in a chest. I hope you enjoy my instructable. If you do please vote.
Step 1: What You Need
What you need to make this is
36 Blocks ( not wood because you will be using lava)
1 Bucket of lava
1 Bucket of water
Make 2 parallel lines each one 6 blocks long and 3 high don't make it out of wood because you will be using lava. I used glass for this instructable so you could see what I was doing. Place 3 signs on the bottom row 1 on the 1st block and 1 on the 4th & 5th on the second row place a sign on the 3rd block and 1 on the 6th.
in the middle of the 2 parallel lines is a dirt line replace the 4th 5th & 6th block with hoppers pointing towards the back. Now put a chest to collect the stuff in the hoppers. Now on the 6th block on the bottom row put your fence gate. Now on the 2nd block on the bottom row place your water bucket.
Now on the 5th block on the 2nd row place your lava bucket. How it works is you push your animals in there using wheat or carrots whatever you want the go in the water and then the lava they die and there stuff is now cooked and it goes into the chest using the hoppers