How Can I Stop My Rooster From Crowing?

We have two roosters: Lenny and Warf. They live in separate pens, each with his own "harem".

Lenny is an Easter Egger and has 9 girls: 1 adult egger hen, 5 egger pullets, 2 white plymouth rock hens and 1 delaware hen. We got him from a neighbor soon after we got the adult laying hen (another egger). We think he's a little over a year old. He's not very smart, but sure does keep his girls in line. And his crow! It is NOT a typical cockadoodledoo ... seriously, it sounds like someone is strangling him!

Warf is a black australorp, 9 months old, and has 6 ladies: 4 blackies and 2 buff orpingtons. He's pretty smart, takes care of his girls, and his crow isn't quite as bad as Lenny's.

The pens are right next to each other but they can't see each other because we have boards separating them. We let out one pen at a time to free range, and put them all back before we let the other pen out. They do see each other from time to time because the front of the pens are a fenced-gate and see-through.

There is a light on all night near the pens, but that's necessary. We have lots of coyote and foxes here, and I need the light on to help my aim, as needed. It's not a real bright light, tho, and the coverings on all sides and tops of the coops/pens prevents most of the light from coming through.

Problem is: My boys crow ALL of the time. Especially Lenny. Could be 2:00 a.m. and I'll hear Lenny going on and on for about 20-30 minutes, then quiet for a couple of hours, then it'll start up again. This time, Warf will start in too. It goes on all day and night.

Yes, it's a myth that roosters crow only in the morning. Seriously. If you're thinking about getting roosters because all of your neighbors are gone in the morning so it won't bother them, don't. Meanwhile, I like that I'm getting fertilized eggs, and in the early Spring, we'll incubate them (hoping via broody hen!).

I don't mind it so much, but my autistic Kid is going nuts with the constant crowing. Wants to get rid of the roosters. Too loud.

This weekend we'll caulk some of the windows to help "soundproof" the house. I can't move the pens any further from the house (and the water spigot). I read some info at: http://www.grit.com/Animals/Secret-of-the-Roosters-Crow.aspx but it doesn't say how to get the roosters to stop crowing. Neither does anywhere else I visited.

Anybody?

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... .. OR ... ...

Should we switch to silkies? I read somewhere that they aren't as loud. BUT they don't produce as many eggs. SO ... we could have a couple of silky hens, a silky rooster, and a variety of other hens. Thoughts?