Monster spawners freeze the world

I created a monster battle arena with 3 mob spawners, one of zombie , spider and skeleton. After finishing the arena and letting the spawners run for a biti left the game. When i came back the next day, i wanted to go check the arena again to make any improvements and the game froze. I have some other structures in the world and i can navigate through them with ease but whenever i get close to the arena containing the spawners the game freezes and i lose some of the blocks i placed before the freeze.