Each cockerel has a different personality.
Don't go into this assuming cockerels are aggressive. But also don't assume it's going to be easy. He's at an age where he might be a bit hormonal. Hopefully that will pass.
Buying more cockerels could work - if you're willing to do that. Sure they'd be easy to find and probably you'd find them for free.
If you want eggs, you could buy some sexed pullets. Look around your area.
Be aware when he firsts sees them he might be rather passionate. To introduce ANY new birds, keep them in aligning pens for a bit. Allow them to get used to eachother before actually putting them together.
As far as the wild birds go.
My chickens have always lived in peace with them. They eat alongside them. They walk around them.
But recently my favourite cockerel killed one. One peck. He had a son he was protecting; maybe that was partly why he did it.
Just be aware it's nature and things like this can happen.
Myself I've had only about nine cockerels over the years. The majority have been absolute sweethearts. I did have one that flew at my face one time. He calmed down a bit.
Are you willing to build a small shed and run? Have you owned chickens before?
Crowing? Well mine set eachother off, at all times of the day. I love hearing my boys singing. If you do have close neighbors, check your laws and make sure you're allowed to keep cockerels.
Ask your neighbours. See what they say. Explain you had a lost rooster come to your doorstep.
I don't recommend crow collars. They essentially stop the cockerel crowing by blocking off the windpipe a bit. Not what I want around my boys necks. I've also seen some photos of what they did to some cockerels necks. Possibly that was when the instructions weren't followed correctly. But still.
If you can't keep the cockerel, but decide you still want hens, go for it. They really aren't much trouble.
