I had some comb issues arise in my flocks after I crossed in some new Marans blood from another Marans breeder and could find very little information about it on the web, so I decided to post what I know about it on my website in hopes that it will help with recognition of this flaw.
This is a genetic issue expressing itself in some lines of the Marans breed of chickens. This particular issue is side sprigs and sprigs. In the show world of chickens and/or if a breeder is breeding toward the Standard of Perfection set in place for the Marans chicken sprigs are a disqualification. They are a disqualification in all single combed breeds of chickens, except for Catalon breeds of chickens where bi-lateral sprigs expressing from both sides of the blade of the comb is a required feature and positive genetic trait (the blade is located to the back of the comb). One breed that comes to mind where this expression is allowed, as it is characteristic of the breed, is the Penedesenca. Penedesenca's are also known for their very dark eggs like the Marans eggs. Rumor has it that some folks here in the United States crossed Penedensenca's into their Marans hoping to increase or darken the egg color. It is reported that it did not darken the egg color, but left some genetic reminders that the cross had been made..such as it's characteristic side sprigs. These rear bi-lateral side sprigs also referred to as "Carnation" comb in the Penedesenca breed have unknowingly and/or knowingly bred forward in the Marans and some lines of birds carry the genes for this type of comb. It is a flaw and should not be used in breeding programs for the Marans chickens.
In the photo below sprigs (bi-lateral sprigs in this case….coming from the Penedesenca) are starting to express themselves in this Marans chick as early as 3 weeks of age. I noticed that this flaw expresses very early in the males and can take as long as 5 months to express in the females if they carry the genes responsible for the carnation comb.
Here it is on a 5 month old Blue Copper Marans cockerel.
Here it is just starting to show on a 5 month old pullet.
This Silver Black Birchen Marans cockerel developed a sprig on the bottom of his blade.
Here is another fault that happens in the Marans and in single combed breeds of chickens, it's called "Thumbprint." Note the indentation toward the front of the comb closest to the birds head just above his eye. Though the thumbprint is a fault and not a disqualification on a single combed breed…it is something that can be worked with in a breeding program.
The other side of the thumbprint comb.