The answer is a firm MAYBE. A lot of things come into play. Do you free range? Do you have adequate space and hiding places? Multiple feed and water locations are a good idea. Even if you do everything right though, it's still going to be a maybe. It's up to your particular birds to either coexist or not. The easiest approach is just to rehome one of them, but that's a decision you'll have to make. They very well could do fine and then again, 6 months from now you could come home to a dead silky.
edit: I found myself with a roo and 2 cockerels this year. It wasn't a lot of fighting, but it was a lot of chasing and resource guarding. I ended up making my pick and culling the other two. My birds are much more calm and less stressed. All of them from pullets to a few years old have come together and formed one flock vs the sub flocks I had before. I think that, at least in my case narrowing it down to one male made a world of difference in the dynamics of my flock. (currently 12 laying age females and one 7-8 month old cockerel)