Are the Fox fleshed? If not, remove fat and red meat under front legs and excess fat from hide and any red meat on flanks. Make sure tails are split.
How long...
1st, fur in
Hanging in area with no heat, turn them in a day or two
Hanging in area with heat, over night or within the same day
Just don't forget to check on 'em from time to time.
If using boards, use a belly wedge
You do not want to dry hide that it feels stiff. You want hide somewhat pliable to turn.
Turn Fox...fur out... and place back onto form to continue to dry.
Comb fur free of dried blood and burdocks. Now comb fur upwards toward head. Let fur dry with hair combed upward.
Leave on forms for several days or until you want to sell.