It was very hard for me at first. I think it is AArt calls this when reality meets the romance of having chickens. And I have always liked Bobbie's idea of one bad moment.
I make the decision much earlier than the deed, and I begin to distance myself from them, I don't stand and watch them, I just feed them and change their water.
It sounds like this is your first experience, so perhaps this will help, but it is highly unlikely, that even if you could keep them, that they would more than likely start to create a lot of problems in your flock. They often fight, overrate pullets, can become human aggressive and some are just all around jerks, even if they are darlings now. This forum is full of instances where the darling becomes the nightmare with roosters.
It is not easy, and even though I have done several, I do have to take a deep breath to do it. As stated above, once it is done, it is not nearly so hard. It will make life much better for the pullets. However, it did take me a long time to eat it, you may not want to do that.
Mrs K