100 too much, uhhhh have fun!!
I think the Sussex are heavier (man I wanted them so badly this year), that's a lot of work, 100!
The good thing about the regular breeds, you don't HAVE to have them done on week 20, you can do some before, or after when you have time and energy. At first it does take a lot longer than expected, until you get the swing of things, then it picks up some, but it's still a lot of work and time. I'd start with 25 for this year, just to get your feet wet and figure out how that works for you, then you aren't trying to work out the kinks with 100 crowing cocks that are potentially over crowded.
If it's having meat in the freezer for year round, may I suggest some turkeys to round out your lot. they really are easy to care for, and one B.Red turkey feeds my family of 5 six meals. IN fact, we just had some tonight for dinner, oh man is that ever good stuff. It takes less turkeys than it would chickens to fill your freezer, if you have the room to allow them to range that is.