Chickens chasing each other and biting at necks

[Gardenlady2]

I have 11chickens that are 19 and a half weeks old. Recently I've noticed them chasing each other around, both males and females. I've also noticed the males biting down on the females' at the bottom of the side of their neck. Is this normal behavior?
I was thinking the chasing and "posturing" may be a pecking-order thing?
And the neck biting a mating thing?
No one has started laying eggs yet....hoping that will start soon.
Due to a coyote attack, I've locked them all back in their coop until we can finish getting the fence up. They have over 5 square feet each plus a lot of roost area they walk around on. The coop is bottomless and we move it weekly so they have fresh ground to scratch in, and the south side of the coop is just chicken wire so they can see out and have plenty of fresh air. I let them run around outside a little each day when I feed them. I've seen the behaviors both inside and outside the coop.
Thanks for any thoughts or advice!

 

[chickenlver2013]

Yes it is definitely normal behavior. This means that your roosters are maturing and ready to make babies. You're hens however are not. When a pullet is not ready to lay they will scream really loud when a rooster tries to mount them. If a hen is ready, they will squat and the rooster will mount and the hens won't scream. However, a hen will grunt when being mounted, but that is normal. I would separate your roosters from your hens until you see that your hens are laying then you can put them together again.

 

[aart]

Or just get rid of all but one of the roosters.