That bird is called by several names such as, Fried, Stew, Roast, BBQ, or just Cornish X. If you intend on keeping the bird monitor the diet, and let it free range for exercise and I believe somebody suggested a aspirin a day. Myself I would put that one in the freezer.
if its over 5 pounds it aint a leghorn i own 6 well a veriety from the leghorn and they are almost 5 or 6 months not sure lol and they arnt even 2 pounds yet
My wife bought some chicks at the local feed store back in April. Six were suppose to be white leghorn pullets and 4 barred rock pullets. If the "white leghorns" she got really are, I'll be a monkey's uncle. They look like cornish x rocks to me. That, or the barred rocks are bantams. I know the owner of that store so I think he and I are going to have to have a chat. Course, if they are cornish x rocks, I have market for them.