They+are+taking+Boxer+to+the+knacker's!

This was pretty much expected because that's what Stalin and his Party did often. Get rid of old workers who can't work, then you wouldn't have to worry about feeding them. Plus, as for the Animal Farm, they get money from the knacker! To them, it's a pretty good deal as well as making the pigs look good and generous once they tell them that they gave all the medial attention to Boxer in the hospital. Plus, in the first chapter, the author writes that the moment Boxer's strength runs out, he'll sell Boxer to the knacker. Well, the pigs are no better than Mr. Jones nowadays, even worse!