Inbreeding Chickens?

[strobl4christ]

I line breed which involves breeding only related birds but in a controlled manner. I often see admonitions on this site warning against the dire consequences of breeding related birds.
People who issue these warnings will tell you that it's absolutely necessary to add "new blood" on a regular basis. Nothing could be further from the truth. In fact the surest way to screw up a breeding program is to randomly add "new blood'.
I have a closed flock [meaning no "new blood" added] of Single Combed Rhode Island Red Bantams that I have bred for 25 years. My feertility is nearly 100% & my hatchability over 90%. I do not have problems with illness or deformity. This is a show line that is probably among the best in the country. Last year I was only able to show 5 times. I showed against the best of the North East Reds & had Best of Breed all 5 times. Three of those times I also had Reserve of Breed. I sure don't see how I could benefit from adding "new blood" to this line.
There's nothing radical about my breeding program it's how most serious & successful breeders approach the breeding process. The people here who warn about the perils of inbreeding are people with little or no breeding experience. If you are happy with the quality of the birds you have there's no reason to cross in another strain. Look up Line Breeding & apply it's principles, you'll do fine.

Are there any line breeding that shouldn't happen like Son to Mother or Father to Daughter? Etc?