There's always a first time, and it doesn't do to assume it won't be your birds next, as Rick's unhappy experience has proved today. "What they would do if a fox made a concerted effort to get at them" is to die a painful and terrifying death, or at least be injured and shocked. Rick was lucky to hear the commotion and get out there in time to save all but one of them.
As for the good layers, top of my lists is Columbian Blacktail. Nice neat little golden brown birds with perky black tails and lay very large brown eggs for their small size, almost every day for a long time. Also excellent are Leghorns or leghorn hybrids, who lay beautiful large white eggs and are gorgeous birds, again quite small in proportion to egg size. They are rather flighty so need some high perches in their run and are not the best for people who like to cuddle their chickens, but go on - and on- and on!