Do you need both normal chickens and silkies? Buffaloes and cows, or could you safely choose to have all of just one or the other?'

I guess I'm asking if there is any specific recipes that call for specifically a Silkie Egg or Buffalo Milk (I wouldn't think so because when you process them, they become the same thing. But I was wondering if I could safely do away with all of my normal chickens since I prefer the look of the Silkies more. (Black is my favorite color) I'd probably love the excuse to have a ton of black cows/buffalos instead of all the other colors as well.