They are probably Fawn and White Runners, just really poor type, production bred birds. Runner type is easy to get far off track in only 1-2 generations, hence the larger size and lower stature. That color though requires at least 2-3 generations of selective breeding to get, so it is doubtful they are mixes. It is doubtful that someone would know enough to selectively breed mixes to that color and yet let the body type completely go so they are probably hatchery type Runners that have just been production bred and lost Runner type.