Hi Bubbles! Personally, I would process extra roosters, but that's just me and it's based on my goals with my chickens. I like to have a productive egg flock with minimal drama, and extra roosters really don't help with that goal.
What you should do depends on a lot of things, first and foremost whether you consider these roosters pets or livestock. Also, you say you have four roosters... if your signature line is still correct, then you've got 15 hens and 10 pullets. The recommended ratio of hens to roosters is 10 to 1, so two roosters should work well with your flock, maybe three once all your pullets reach maturity. With four, you have increased risk of roosters fighting and hens being harassed and stressed from all the breeding.
Another thing is, if you had these two roosters processed and bought another rooster to replace them, yes that would be three roosters so from that perspective it might be okay. But adult roosters do not accept new adult roosters. There would be a lot of fighting and bloodshed. Do you have a plan for how to handle that? Either you'd have to keep the old and new roosters separate, or you'd have to raise a young cockerel as part of your flock so that he would be less apt to challenge your existing roosters.
Then if you're planning to hatch chicks, 50% of those are going to be male. Do you have a plan for them, if eating them is going to upset you too much? Roosters are very tough to rehome, even without any special health or behavior problems.