There's yoke ,but no eggshell anywhere what could be wrong ?

[Denise Mic]

Her shell gland is acting up either due stress, diet, or infection will cause the lack of shell formation. Once or twice is okay in a hen this age but if it continues you may need to investigate further.

She is just 2 years old is this common at this age?

 

[BlindLemonChicken]

My memory isn't great but I've gotten the odd egg from layers that aren't new to laying. I had an Americauna that would lay the occasional weird egg when she came out of molt. Probably around the time we had a raccoon attack too was the last time it happened.

 

[theoldchick]

She is just 2 years old is this common at this age?

Only if she is stressed by weather or possible flock dynamics. Keep an eye on her.