Almost immediately, life on the farm, under the pigs, is difficult. The problem is that the animals do not see it. They believe in the ideology of animalism so much, that they actually believe that they are better and happier, when in fact, the situation is worse. Let me give you three examples.
First, eventually there was less food for the animals on the farm. Here is what the text says of Boxer:
Sometimes the long hours on insufficient food were hard to bear, but Boxer never faltered.
The point is that there was less food and the work was harder. This makes sense as the project of the windmill broke twice twice before it was built. And finally when it was built, it was not used to make the lives of the animals easier. The mill was used to grind corn for profits.
Second, many of the animals were looking forward to retirement, but no one actually retired. Here is what the text says about Clover:
Clover was an old stout mare now, stiff in the joints and with a tendency to rheumy eyes. She was two years past the retiring age, but in fact no animal had ever actually retired.
This shows once again that life was worse under Napoleon.
Finally, when there were possible detractors of Napoleon, they were killed. The massacre that takes place as Napoleon is consolidating his power is brutal. Nothing like this ever happened under the rule of Mr. Jones.