I have been sent pictures of Ideal Hatchery and other hatchery Dutch that people purchased as chicks. They are not true Dutch, While they will be nice backyard banties and fun to have decorating the yard ands eating bugs., do not expect DUTCH. Several who received them, but wanted true Dutch for breeding and/or possible showing, sent me pictues of their birds--not at all the lovely Dutch they expected, and they just dumped them and located breeders of the real birds of Holland, real glamour--totally unlike OEGB or other Bantam breeds. White earlobes and blue legs do not make a Dutch Bantam--and hatchery dutch often do not have either. There is lots more--and you rightfully mention TAILS.
Broodiness is probably inherited and hatcheries have no clue about broodiness, as all eggs (often purchased and no way to know what it inside those eggs, even the breeding for sure) none are hatched by broody hens. All Dutch are not setters. I only keep daughters of setters and keep no pullets that do not set their first 6-8 months, after their first session of laying--usually at about 4 1/2 mos. (I do not hatch pullet eggs, however, preferring the larger p;ullet eggs from the second "set". ) I raise several varieties, including Mille Fleur Dutch (imported from Holland) and my friend received an order from a hatchery that arrived with FEATHERED Feet! She ordered DUTCH, not Belgians, that the hatchery offered. She gave them away and waited for my hens to hatch Mille Fleur DUTCH.
So, you takes your chances. We NEED hatcheries, but wish they would not offer crossbreds as dutch, and/or in varieties that do not exist in Dutch--it does the breed no good. Jean R