You can pretty much see what Farmer Jones's main vice is at the very beginning of the book. In the first few sentences of the book, we find out that he is too drunk to do a good job of closing up the henhouse. Even though he's that drunk, he gets himself one more glass of beer before going to bed.
In the next chapter, we see that it is Jones's inability to control his drinking that causes the revolution to start up. He gets so drunk in town that he passes out and forgets to feed the animals.
Mr. Jones' vice mirrors the struggles of the Romanov family at the end of their reign. Considering why people are drawn to alcohol, the reasons may be many, but prior to the Russian Revolution (and probably afterward), the Romanovs began to care less and less about the Russian people. They drank for reasons maybe of boredom or even depression because of their inability to engage the people. Thus, George Orwell creates an interesting piece of Mr. Jones character for us to seek as followers of the allegory.
In the very first sentence of the first chapter of George Orwell's novel, Animal Farm, we find the owner of Manor Farm, Mr. Jones, "too drunk to remember to shut the popholes." Jones loved his liquor too much, just as the next leader of the farm, Napoleon, would.
It was Benjamin who first realized the true final destination of Boxer. He pointed out what was written on the side of the truck in which Boxer was being transported. Before Muriel could read it herself, Benjamin spelled it out for them: "Alfred Simmonds, Horse Slaughterer and Glue Boiler."
Mr. Jones' main vice is drinking excess of alcohol. This clearly outlined by Orwell in the very opening paragraph of "Animal Farm.'
Mr. Jones, of the Manor Farm, had locked the hen-houses for the night, but was too drunk to remember to shut the pop-holes. With the ring of light from his lantern dancing from side to side, he lurched across the yard, kicked off his boots at the back door, drew himself a last glass of beer from the barrel in the scullery, and made his way up to bed, where Mrs. Jones was already snoring.
Alcoholism was also a vice of the Czar of Russia at the time of the October Revolution. Mr.Jones is the counterpart of the Czrar.