That sounds like rich ground with all that water and food available , perhaps you should hang a well camoflaged trail cam and find out . Sixty acres is almost 1/10th of a square mile , what density per square mile does that area hold consistantly ? Whatever it is divide by 10 and you'll have a reasonable approximate . My area holds about 30-45 per square mile , so the average for a plot that size would be 3.5-4 with probably one being a buck .