A normal feather, fully grown in with no blood in the shaft.
For an illistration of a blood feather, see here.
Blood feathers, also know as pin feathers, are new feathers that still have a blood supply to their shaft to support growth. When one becomes broken, the resulting bloody mess can panic bird owners. Blood feathers can be broken from flapping or banging against the inside of a cage, from a fall, or a wing trim gone bad. Dealing with the broken blood feather is really straightforward, and no cause for drama.
Identifying a Blood Feather
If you've never seen a blood feather on your pet bird, take some time to look at the lower portions on the shafts of the large primary flight feathers on your bird. All feathers start out as pin feathers when they first grow in, but the bigger flight feathers are just the easiest to see.
Most of the shafts will be white, and sort of see through, clear, with full feathering already in place. A blood feather, however, will have a thicker shaft that is dark purple. The color is from the blood filling the inside of that shaft to feed that growing feather. The blood feather won't be fully grown in yet, and may only have a little bit of feathering at the tip that has come in so far. If you don't see any feathers that fit this description, just keep checking back ever few days or so. One will show up eventually.
Read more here.
