
Unfortunately all to common. Were the dogs Hip Scored, and Haemophilia tested (for males) etc?
Legally a bitch is allowed to have 6 litters (I expect puppy farm ones have more as pups not registered so no way of knowing that).
Most of us are very pleased that from January next year the maximum number of litter that can be registered with the Kennel club from any bitch is 4, that's a maximum not a must.
Something the size of a GSD I would think 2 1/2 the youngest I would want to try breeding, two in most medium size breeds.
With the KC accredited breeder scheme many more limits are being asked for regards age fo first litter being higher than the minimum of 1 at mating which is only appropriate for some of the toy breeds.