If Lynn is right and they are Partridge Rocks they will be fine during the NJ winters. I have the same breed, but different varieties - white, barred and buffs. I agree with OHChick and Greenmulberry about not being able to sex them so early. I have some that are six weeks old and they all have combs that are getting very red and they are definitely all females. It's difficult to sex them as young as yours are so I wouldn't start to worry about that just yet.