Ajablu, it's sounds like you may have gotten something other than a broiler cross, maybe your pretty white chicken is a rock. As for roo or pullet, look at the feathers on the back, down toward the tail. Are the tips pointy or rounded? Pointy feathers mean a roo, rounded and you have a hen.
Beerguzzler, if you do decde to raise a few meat X hens, here's what I found when I did that:
They get huge, but once they're grown don't eat nearly as much as the y do when young. They will lay nice big brown eggs, mine laid quite a few enormous double yolk eggs. (those won't hatch, BTW) When mine got near a year old, they started to die off. By the time I only had one left, I'd figured out that what was happening was congestive heart failure. When they were at rest on their keels, the combs would turn deep purple, and the breathing was bubbly, from fluid in the lungs. When they got up and moved around, the combs would return to a normal red, as the circulation improved while standing. One they get to that stage, you may as well eat them, they won't last much longer. With more attention to diet and activity, they can live longer than mine did. These were some of the first birds I had, many years ago, and I knew nothing about meat birds at that time.
We went ahead and butchered that last one, (Bertha) she dressed out to about 15 lbs., like a small turkey. From the size of her heart, and the amount of fat in the body cavity pressing on heart and lungs, I know she wouldn't have lived much longer.
Good luck with whatever you decide to do.