I know nothing about the behavior of Gambles. I have/had 7 Adult Bobs (6 male/1 female). This will be their 3rd summer, born and raised together. I have never had any problems with them in the past. They have all kinds of room to get around/hide/perches/etc. (160 sq. ft.) This spring they are killing each other off. I now have 4 left (3 male/1 female) at this time, except for my 81 newborns! I'm sure that my problem is a breeding/territorial thing, in which may be your problem also. Although my Bobs have never harmed a hen. I'm just not sure why I've never had this problem the past 2 springs.
Mine may have just started being aggresive because of their age? I don't know.
Just food for thought.