We caponize our bresse cockerels on the farm. Maybe you will get lucky with no crowing, however, yes, they can still crow and they will still mate with the hens. They will just not be able to fertilize the hens eggs. If the cockerel was not captioned properly, he can also regrow their testicles and be able to fertilize the hens.
If he wasn’t canonized properly he will not ‘regrow’ testicles. He is only using the tissue left behind in the botched procedure.
Chemical castration of roosters and/or drakes, ganders, etc (pre-pubescent and mature birds) can be achieved via off-label use of an anti-testosterone implant designed for use in dogs. It's called Suprelorin and is a vet-only product requiring some expertise to achieve painless injection into the breast muscle of birds (it's a whopping great 12g needle).
Pros are fairly obvious: no testosterone based behaviour (cranky roos that attack you, randy drakes that rape your gumboots, etc); AND if performed in the pre-pubescent or pubescent bird [before crowing becomes a learned behaviour], will eliminate crowing; no fighting between the boys over the girls (or lack thereof); zero fertility after about 5 days in implanted birds so you can be sure who daddy is going to be.
Cons are a bit more complex. Aside from the off-label use (which just means your vet needs to explain to you that this medication is not registered for use in avians but has been used in practice enough for him/her to be satisfied that it is safe), the cost can be inhibitory if you are implanting lots of birds. I generally use the six-month implant in avians when implanting an individual for the first time, and we can get 2 years + of fertility control in some birds at this dose. Others will wear off right on the six months and the next time we'll use 12 month implants in those individuals. I have a feeling it may be weight & metabolism related, but I'll have to do a few more before I'm sure, as I've only implanted a dozen or so birds at these stage - and mostly parrots. Cost can range from $80 - $120 and upwards per implant depending on your vet & which implant your bird needs. Variability of length of control can be another issue - because we don't necessarily know for how long the implant will control fertility as mentioned above. The bird can also never be eaten after having the implant (but that fits if the reason you're implanting your extra roos is that you don't want to eat them). Males can also lose their secondary sexual characteristics and become somewhat feminised in appearance in comparison with an entire male bird. But as long as you don't call them sissies they seem not to mind.
Joking?
My wyandotte bantams are squeaky as young adolescents, but not as adults. of course they aren't as loud as LF, but loud enough......
