They're breeding chickens to have larger breasts because so many people only eat the white meat. Have you ever bought the leg & thigh portions you can buy by the bag for 49 cents a pound? Some are very deformed. Have this mental picture of what those chickens must look like with deformed legs and huge breasts.
This time I bought the IQF breasts (just way to convenient NOT to have on hand) and realized that in order to get the weight on the label I got a portion of a half of a breast. In truth, it worked well for me. A lot of these breast portions are so huge that one will do for both of us for dinner if it is something like a stir fry or anything sliced/chopped/diced in a sauce. Sometimes it is a two are too many, one not enough situation, and that piece of chicken that isn't an entire portion is good.
I've lived in a small town for ten years now, so sometimes don't know what is available any more. I used to be able to buy bags that were smaller breasts or ones that were larger.