The little spiky pins are just that, pin feathers, and depending on the specie of bird, can end up as much as 12-14 inches in length.....
As feathers grow, there will be blood in the quill, providing nutrients to the growing feather, hence, blood feather. Once the feather has completed its growth, the blood will recede back down the shaft & the follicle will its access to the blood supply.....
While many refer to a bird's molt as an adult molt, that's kind of a misnomer because some birds don't really reach adulthood/sexual maturity until they are a few years old ans several molts past their weaning/fledging.....
Feathers can be replaced outside of a normal molt...like when a feather is lost/pulled out from getting caught in a cage or if a dog, cat or other animal gets a mouthful of feathers...in those cases, the bird's body will replace the missing feather outside of a normal molt.....now, if a feather is broken for some reason, the bird's body will not replace it unless the feather is removed from its follicle...usually by you yanking it out.....
