Pick out two animals that have left the farm and two animals that have survived. How have the survivors changed?

Hi Tea! 

So I've been reading this "book" over five times and I've been analysing it also.
I would say that Boxer (as one of the survivors) hes temper changed alot after he survived. 
Squeler, when she survived, she got ill when ever she saw  the pigs or Mr. Pilkington.

Benjamin and Moses left. 

Moses wanted to have more apples but he didn't get any, so that's the reson why he left. 

Benjamin left because the horses ate too much syrup.

There you go Tea, that should do.