I really don't know what to say.
I once knew an old Cajun lady that told me to set pullet eggs if I needed more hens and rooster eggs if wanted more meat. She then went on to show me a bunch of eggs and gave a lesson on how to tell what the chick will be that hatches from them. I really didn't think this was possible, but I can assure you that she must have known something. I never really saw what she saw in the eggs. But I never forgot her lil teaching.
When I got back into raising chickens a while back, I knew if it was for eggs only that I wouldn't come out ahead, but I had to look at the big picture. How much for the eggs? How much could I save on chicken meat? How much for not running the lawnmower? How much for having my garden more fertile? How many bugs will be eaten instead of eating my oak leaves?
I admit that when you first start slaughtering and you are a bit unsure of yourself, you will not feel very good about killing your extra roosters, but as for the reasons I got into poultry again, I would just say I had to tough it out and do what I needed to do. If you can kill and clean, but feel funny about eating them afterwards, perhaps you can soak them real good to clean out the meat and freeze them for a week or so and then when the memory of the unpleasantness is behind you a bit, go ahead and cook it, keeping your additude as positive as you can.
I like my birds, but I try to like them, without thinking on them as pets. I think of them as livestock that I will eventually eat. I will get what I can out of them and replace them before I eat them, but they are all really destined for the soup pot.