something wrong with my rooster

hello everyone, i am new to this site and am hoping that i can get some help. i have a rooster that is about 5 and 1/2 years old, not sure of the breed, but he is larger in stature then my laying hens so i am thinking he is more of a meat bird. over the summer we noticed that he would stumble here and there, but nothing major. over the last week or so we noticed that he stopped crowing, and is having a really hard time walking. he no longer roosts at night, but sits on the floor of the coop. he is still eating and drinking good we had a problem this summer with a weasel or something that took most of our flock, now we lock them in their coop at night. we have had chickens for like the last 10 years and never had any trouble like that. we do love having the chickens and the fresh eggs, can't beat it. but the rooster i am talking about is the only rooster left and the oldest in the flock. we really don't want anything to happen to him if we could prevent it. is this due to his age or could something else be going on with him. for all the years that we had chickens we never saw anything like this. oh and he holds his tail feathers down and uses his wings to balance. it is so sad to watch. any advice or help would be appricated.
thanks so much

 

thanks sourland for the reply. and yes we do too understand the slowing down thing. we were kind of figuring it was an age thing with our rooster. he will be missed alot when his time does come for him. he will be made as comfortable as poss. we put extra straw on the floor of the coop for him and we take the food and water to him so he doesn't have to walk so much. thanks for the advice