I recently introduced them to the big run and have noticed I have one that keeps trying to crow how can i tell for sure if its a rooster or not??
Crowing = cockerel (= young male)
Photo looks like a cockerel to me.
In general, the comb and wattles will be bigger and redder on cockerels than on pullets of the same age and breed. (Starts when they are a few weeks old, and gets more obvious as they get older.)
By the time they reach the age of your bird, the cockerels will have saddle feathers that are narrow and have pointed ends, while the pullets will have feathers with rounded ends.
"Saddle feathers" are the ones that are just in front of the tail, dropping down, and are narrow and pointy. I'm pretty sure I see them in your photo. Some of them are hanging over the tips of the wings.
I currently have all hens till I added these chicks not sure I want a rooster in with the flock. How can I tell and what should i do??
If you do not want to hatch eggs from your hens, you do not NEED a rooster. Whether you WANT one is for you to decide.
What to do?
--Keep a rooster anyway
--Give or sell the rooster to someone
--Eat the rooster
If you keep the rooster, you have the choice to change to another option later.
If you give away or sell the rooster, the person might keep him for breeding purposes or as a pet, or they might eat him.
Eating the rooster is the perfect solution for some people, and unthinkable for others. I don't know your feelings on the matter.