I think the key is that, no matter how they may affect them initially, the final meaning is "determined" by the pigs. When something shocking happens, the propaganda machine kicks in and provides them with an explanation that calms their fears --- and this, of course, is the essence of how their state works. So when they come for Boxer, who is no longer useful to Napoleon and the state, and come with a van that is clearly identified as a horse slaughter truck, Squealer tells them that that's not the case. The veternarian has bought the truck, but has not had time to paint it. Although this is total nonsense, the people believe it, perhaps because they need/want to or perhaps because they have just grown so numb that they no longer question anything.
So, perhaps, the executions might be making them better "citizens" instead of more fearful ones ... if they can believe this, they can believe anything.
In the world of the Internet and information overload, we can certainly learn something from this!
As you might guess, after seeing such an outrageous slaughter happen right on front of them, the animals are subdued and frightened. The blood and the violence were bad enough; what seems to me to be most disturbing to them is how mundane and relatively innocent many of the offending acts were. Urinating in the drinking pool, hoarding several ears of corn, chasing a sick ram around the fire. These are not offenses typically punished with any sort of violence, if they're punished at all. The "confessions" which were revealed were weak and seemed to be motivated by fear more than anything else. This "purging" in Orwell's novella Animal Farm served to remind the animals that they must maintain their loyalty to Napoleon or there would be consequences. This fear lasts a long time and is extremely effective; there are no more serious uprisings during Napoleon's reign. This is when the animals should know for certain what will soon be painted on the barn wall for all to see:
"All animals are equal, but some animals are more equal than others."
We are told about two different ways that workers are affected by these events.
First, we have Boxer. He reacts in his usual way. He thinks that if things are going wrong on the farm, it must be because of something that they, the workers, have done wrong. So he is determined to work even harder.
Second, we have Clover. Her response is much more understandable (to me at least). She feels very sad. She feels that all of this kind of oppression is not what the animals had worked for as they got rid of Jones and human oppression. We see this in the following quote"
If she could have spoken her thoughts, it would have been to say that this was not what they had aimed at when they had set themselves years ago to work for the overthrow of the human race. These scenes of terror and slaughter were not what they had looked forward to on that night when old Major first stirred them to rebellion.
It is important to note, however, that Clover (like Boxer) decides to keep supporting Napoleon.
The animals were bewildered and confused by the mass slaughtering of the animals. They thought that by killing other animals, they had broken one of the seven commandments already. But being fearful for their own's lives, they did not voice out their opinions, scared of further backlash. Boxer make them even more certained that everything would go back to normal, as he had decided that it must be due to some fault of themselves, and they had to work harder from now onwards. Clover, on the other hand, despite being confused and repelled about the brutal violence, she is still loyal to Napoleon. Unable to express his innermost feelings, she led the animals to a mournful signing of "Beast of England".
Everybody felt that the killings were wrong and morally incorrect. We might have thought that by the killings, they would have somehow revolt against Napoleon for his brutality, but the shocking thing that they seemed nonchalant about this matter, and did not question the supposed "confessions" of the animals that they were in cahoots with Snowball to bring harm to the farm. They were numbed into believing all of Napoleon's deceptive lies, so more prone to brainwashing and manipulation.