@vpatt
The chest bumping is power play. The calling over for tit bits that he's found and dancing is courtship. As a young rooster it is good that he is doing the dance first. Often it takes time for them to learn the finness of courtship and adolescents with raging hormones often just grab a hen and try to mount, without showing any attempt to seduce or waiting for the hen to acquiesce. The hens flaring up their hackle feathers and chest bumping him are saying they don't accept his advances. It's a bit of a put down for him poor lad!
At the moment he will still be gaining confidence and will stay within his peer group, but if he is your only cockerel, then eventually he should win over most if not all of the other ladies.
Don't worry too much about him mating with his siblings as they will mostly be half sisters anyway(probably same father but different mothers). It is only an issue if you decide to hatch some of their chicks and even then, it is not so much of a concern as with other species although mother to son or father to daughter is safer line breeding from what I have read, than between siblings.
 
So pleased you are enjoying the different behaviour that a cockerel exhibits. I do love having cockerels both for the eye candy and their role within the flock. Do be aware that they can change and become violent and aggressive both towards the hens and you. When dynamics within the flock change, it can trigger a change in their behaviour, sometimes for the worse. Just wanted you to be aware, especially if you have children around the chickens. It's worth while, 2 or 3 times a week, walking straight at him so that he has to get out of your way. Make strong eye contact and be clear that you are the boss. This reinforces who is top dog and discourages him from challenging you. I had an issue with one of mine and he drew blood from my leg a couple of times before we got it sorted out. Now I am much more conscious of his body language and if I think he has looked at me askance, I walk straight at him and make sure he walks away from me. Once he does that, I ignore him and can turn my back on him and get on with whatever I was doing.
 
Anyway, good luck and I hope you have plain sailing with your flock.
 
Regards
 
Barbara
 
PS. Re reading my post, it sounds like my cockerel is mean and that's so not the case. He was lovely when I first got him but I tried to introduce another rooster into my flock and they fought at every opportunity. I eventually had to remove the other cockerel as he was being hammered and it wasn't settling down. The day I took the other rooster away, Handsome Harry decided he would have a go at me instead. It was a bit of a shock as he had never shown any bad behaviour towards me before and it took a few weeks before we got it sorted out, during which time I couldn't afford to get caught in the yard empty handed and had strategically placed brooms and shavings forks to fend him off and pin him down if I needed them. We have mutual respect now but I am aware of the need to monitor and reinforce my position with body language every now and then.