‘Duck Dynasty’ reigns, but have the Robertsons reached their tipping point?

Talk about a publishing “Dynasty.”

A&E’s “Duck Dynasty” cast currently has three books on the New York Times Nonfiction Bestseller List, and the matriarch of the Robertson clan, Miss Kay, also has a cook book out. Meanwhile, Alan–the clean-shaven brother who made his debut on the fourth season– released a devotional, which contains “365 days of inspirational messages,” and it will be available in either pink or brown camo (of course) on Oct. 15.

Not content with just five books, the Robertsons are set to release three more books next year, including, “Faith in the Duck Blind,” by Jase Robertson, “Phil-Osophy” Phil Robertson’s second tome, and “The Women of Duck Commander,” a collaboration between Miss Kay, Korie, Missy, Jessica, and Lisa Robertson.

The family has also launched a line of greeting cards, fan T-shirts and they still sell their famed duck calls. Heck, we love them here too. The entire cast appeared on “Fox & Friends” every morning for five-days straight, as part of a highly promoted segment during Elisabeth Hasselbeck’s first week on the show.

Considering the reality show also repeats several times a day on A&E, could this all be too much “Duck Dynasty” for one nation to handle?

In a word, no.

“Duck Dynasty is very popular with our customers,” a manager at Bass Lake Pro Shop in Rancho Cucamonga, Calif., told FOX411. “Some things we definitely have a hard time keeping on the shelves. We can’t keep the Uncle Si cup in stock–that plastic cup he drinks sweet tea out of. The duck calls always sell out. And Si’s book, ‘Si-cology 1’ does very well for us.”

The Robertsons merchandise sells so well because the family is relatable, he said.

“I think that they appeal to our customers because of their values,” the manager explained. “They’re sticking together, even with the country the way it is now. I think everyone can relate to that."

But some experts caution that the “Duck Dynasty” clan may be in danger over-exposing their brand.

“They have coffee mug, T-shirts, key chains–you name it,” Kevin Meany, president and founder of South Carolina-based creative firm BFG, said of the brand’s ubiquity in mass market retailers. “This just seems like a huge explosion of stuff. Consumer fatigue with this brand is a real risk.”

Either way, from a business perspective the Robertsons are doing the right thing by releasing all these products—especially the books—now, Lorraine Shanley, president of Market Partners International, explained.

“I think that they’re striking while the iron is hot,” she said. “I presume that they’re being very responsive to the feedback they’re getting on the show. It’s smart on the publisher’s part and it’s smart on the Robertson’s part... It’s particularly interesting that Howard Books is publishing them, because that tends to be a religious imprint within Simon and Schuster.”

But has the “Duck Dynasty” frenzy peaked? One executive at a major entertainment company—who wished to remain anonymous—told us the “Dynasty” madness isn’t ending anytime soon.

“I feel like ‘Duck Dynasty’ is a growing franchise. They’re on the rise, and now is the time for them to put these products out,” the exec said. “The Robertsons are very savvy, and I think they have the ability to play this right so that they can establish a brand for themselves like Martha Stewart, which is an evergreen lifestyle brand.”

And though the Robertsons come off as a “normal” family who just happened upon fame, the executive speculated that everything the “Duck Dynasty” cast does is strategic.

“They’re not dumb people. Part of the appeal of their show is that they are aware of what they’re doing. They’re polishing their own brand, if you will. They’re not being manipulated as much as I think they’re manipulating the media to their benefit.”

But one troubling sign that things might be turning against the duck call moguls: they graced their first two tabloid covers these past two weeks, with a photo of Willie and his daughter Sadie on the cover of Life & Style this week with a headline that blares: "A Father's Fears: I won't let fame destroy our family!"