Is the Great Valley vulnerable to Sharp Beaks?

[LittlefootAndAliTogether]

Let's face it, I think the greatest threat, and also the harder to notice, unlike Belly Dragger invasions (why haven't Dil and Ichy tried to get into the Great Valley? Dil's kind can do it without there having to be holes in the Great Wall and Ichy's kind can fly.), Sharp Beaks are smaller and can make off with Swimmers and Leaf Eater Flyers before they get noticed.  (Especially if they go at night.)  

Heck, Red Claw could recruit them to try and carry off Chomper to him.  (Yes, Chomper has something the Leaf Eaters don't: the ability to bite back, but still, if they come in numbers, he could be in trouble, especially as they have an ability Chomper doesn't: the ability to fly.)  

[DarkHououmon]

Dil likely didn't try to get in cause maybe she doesn't know about it. Plus to get there, she has to cross a vast desert and that isn't good for her kind. And of course, she'd need Ichy, whom she knocked away at the end of the 4th film, and seems to hint the end of their partnership.

As for sharpbeak flyers, true, they could get in. However, there are plenty of flyers in the valley that could ward them off. Plus sharpbeaks probably would only try going after children, really young dinosaurs, and there are plenty of adults around to keep them away. Sharpbeaks are also more fragile and light, meaning a blow to them is more devastating than with a terrestrial animal, so they would be a lot more cautious.

In the end, it's possible their reason for not coming into the valley isn't so much that they can't; it's that to them, it's probably not worth it, considering the valley's reputation.

[Malte279]

My personal mindcanon is that no matter the species sharptooth in their right mind (which may exclude Redclaw and the original sharptooth) would actually WANT to get into the Great Valley. In LBT 2 we have Chomper's parents leaving the Great Valley on their own accord once they got their son back and while LBT 2 still suggests that the Great Wall protects the Valley LBT 6 suggests for the Great Wall to be not quite as impenetrable as the earlier sequels suggest.
Thing is that the Great Valley seems to be a rather dangerous place for sharpteeth to be with the residents teaming up the way they do. Attacking stragglers of migrating herds or the like outside the Valley seems to be a much less risky approach. I would not be surprised if the Great Valley held a similarly creepy reputation to sharpteeth as the Mysterious Beyond does in the early sequels. After all we see a number of sharpteeth being killed in the Valley or its immediate vicinity throughout the series (original sharptooth, sharptooth from the lone dinosaur legend, two sharpteeth being executed by live burial in LBT 6, sharptooth from LBT 8 most likely dead too (unless memory fails me)). If I was a sharptooth I would certainly go for a less dangerous hunting ground.