iow many hens/pullets do you have? It seems like you are new to keeping chickens and may not be aware that keeping two cockerels/roosters within a small flock can cause the hens/pullets a lot of distress and the males may fight with each other, especially when they have not been raised together.
I see you also have a duck.... is that male or female? Keeping a drake with chickens can also cause health and wellbeing issues, unless you have plenty of female ducks to keep him happy. When they are young it is not a problem but once they hit adolescence and their hormones kick in, things can go horribly wrong very quickly, so it is important to be prepared.