Soft egg?

[TinyBoxTim]

Today after 3-4 years of having a small flock got a soft shelled egg, it made me laugh and I showed it around like an oddity to my family but how do I keep it from happening again and is it Ok to use? It was a pullets first egg

 

[aart]

Pullets often lay soft or thin shelled eggs in the first month of so of laying.