Well... since it is a single chick, I would introduce them at about 2-3 months and not let them stay together till it is about 4-5 months old and can hold her own... if it is a her * crosses fingers*
I do not know much about chickens. This is my first time raising them. But my 2 weeks old baby is developing a comb, has alot of feathers and I see one small dot on each leg where if it is a rooster it would grow its spurs. I hope that this is not an indication that this is a rooster. It has become so attached to me (I guess because it is a single chick) that I would hate to have to find it a new home.