Bearded dragon invertile eggs

Question
My male beardy has mated with my female yet she laid 20 invertile eggs,they collapsed 2 weeks after being incubated,my female is showing signs of being pregnant again,will these be invertile as well,we don't understand as we saw them mate,please help,many thanks Kat .

Answer
There are many things that may have gone wrong.  The male may not be fertile, or it may just have been bad luck.  Have they been breeding since the first clutch was laid?  Are both animals healthy and have good body weight?  (If the animals are too young, they may not be fertile, either).

What type of incubator are you using, and did you find the eggs promptly, and place them in it?  Have the incubator temperatures been stable?

Come to think of it, the fact that your eggs took 2 weeks to collapse suggests they were fertile when they were laid.  While I do not breed bearded dragons, I do breed ball pythons, and infertile eggs generally begin sinking only days after they are laid.

Here's a good page detailing more information on incubating bearded dragon eggs, including issues that may arise.  
http://www.bio.miami.edu/ktosney/file/BDeggs1.html
One of the biggest dangers for any reptile eggs are incubator temperature spikes.