All birds have Scapular feathers (Spades to we fly tiers) They start at the Humorous (first joint down from the shoulder) and run up across the back, between the cape and saddle hackles. Larger in size is in the middle (over the back bone) getting smaller as one goes back down the other wing. I doubt if they could be "bred out". Note all birds, not just chickens have this spade feather. Very small spades will be found on the wings of the bird. Note: Roosters have a pointed end to the feather and hens are rounded. (this is one of the ways we sex very young birds) Spades for we fly tiers normally come from the rooster. If you select spades from a hen it will be rounded on the end, not pointed.
We here at Conranch choose to not cut them off from the cape or saddle.
Some breeders do cut them off and package them for sale. We do not. If you buy a cape or saddle with no spades, rest assured it has been removed and perhaps is in a small package someplace for about $5.95. + -
If any of you have one of our capes or saddles you do have about 1/2 the Spades the bird had originally. The first cut we make when doing capes & saddles is across the back of the neck, so 1/2 the Spades are on each piece.

Of course like hap says, the "full skins" we produce have lots of feathers you will not see in a shop. Many commercial tiers, customers of mine buy their hackle in full skins.

Sometimes when I have a beautiful color, in the wings I will cut the wings off and bone them out, just for the special spades. Mark left & right so a tier can make matched pairs. I seldom have any for sale, only on special requests.

The spades are considered wet quality, not dry.

There you have it, Spades.

Denny