Why do the animals on Animal Farm admire boxer and what is boxer demises?

Boxer is admired by animals on the farm because he works so hard and is so strong. They want to be as devoted and able to the work as he is.

Boxer fell while hauling stone for the windmill and hurt his lung. The pigs say they are sending him to a hospital in Willingdon but when the cart comes to pick him up, Benjamin points out what is written on the side of the cart "Alfred Simmons, Horse slaughterer and Glue boiler, Willingdon. Dealer in Hides and Bone-Meal. The animals realize that they are sending him to his death and try to get the cart to stop but fail. After he leaves, Squealer tells the animals that Boxer died in the hospital. He says he got the finest treatment and Napoleon didn't hesitate to pay any price. Squealer also explains that the cart says horse slaughterer on it because the hospital bought it from them and hasn't yet painted over it.