It’s kind of hard to tell. I’d wait a few months and start checking their legs for small signs of spurs, their combs and waddles, their back feathers,(if they are curved and arched it’s a rooster. If they are wide and broad it’s probably a hen) Anyway time will tell what gender they are sometimes you’ll have to wait until, they crow or lay. They still are very cute.
#1. Barred Rock cockerel
#2. Barred Rock cockerel
#3. As stated, either White Rock or Leghorn, and likely pullet (although I can't see the comb well enough for my gender guess to be accurate. Time will determine which.
#4. White Rock or Leghorn, cockerel
#5. White Rock or Leghorn, cockerel
#6. Austra White? pullet
#7. Most likely either Black Australorp or Black Jersery Giant, depending on color of foot bottoms. Yellow = Jersey Giant. Pink = Australorp. Nothing screaming cockerel yet.
Although some do indeed appear to be pullets, there's potential for change since they're still a bit young.