Cockerel Contraceptive?

My mum has got snowed under with chicks recently, she had been taking the eggs out daily but there was some sneaky hens that have been making nests in the flower beds and borders and more and more chicks keep showing up! Today we gave loads away but don't want to be in that mess again!
Someone said you can put something on the cockerels neck to stop him mounting the ladies, is this right or was he meaning strangle the thing?
Any suggestions please?
Thanks

Your mum is probably thinking of the old caponizing pellet which i believe is now illegal in this country.

Ah thanks for your replies, I was hoping it was some kind of simple collar or something.
At least now there are fewer birds she can keep an eye on where they are going (very free range) and count them all to be sure none are hiding and sitting!

Pepsi, caponising a cockerel whether via surgical or chemical means is illegal in the UK.

Thats why I havent seen them any more

My Mum's butcher used to import them from France at Winterval, because people still asked for them.

So it wasn't banned by the EU just by the UK?

It probably was, but ignored by the French, but the good old UK abides by the rules of the EU