Tim, you explained this REALLY well. My daughter volunteers at a farm and one chicken went broody and the owner was worried. I sent her a link to this thread....I have learned SO much from BYC.
I have no Roo, so my hens used to hatch ducklings....I have always simply firmly grabbed the eggs that were chicken. I got pecked only a few times, and I peck back with a finger.
The MAMA duck, that is a totally different story....SHE is a nasty girl when she is broody. I usually have to fake with one hand, and grab her neck with the other, then I can cover her head while I fish out the chicken eggs. Sometimes I will pull her out (she screams at me the whole time) and I will candle with my girls to see if I have ducklings or soup. Soup gets tossed, ducklings get monitored. I have had many successful hatches from her, she is great.
I have a Bantam that hatched three babies, and one got trampled. The other two I pulled out to protect. She is the ONLY Bantam I have except the babies (4 in all) and was sitting on over a dozen duck eggs....LOL See my pics to see her. I have no clue why I can't attach them.