Fart eggs are usually
very tiny, hard shelled but often have no yolks.
A softshelled egg, with just membrane and no shell, is not uncommon in newly laying chickens and I assume also turkeys. The are often laid in odd places because they feel different and often take the birds by surprise when they emerge....birds can often act very strangely (isolating, inactive, standing stock still for quite some time) when one is passing down the 'pipe'. After it's out, they go back to their regular routines.
It's because the shell gland is not fully functioning yet, a glitch so to speak...one once in a while or several in the first month or so is nothing to be alarmed about.
Might want to post in the
turkey forum in case there's something different in regards to softshells in turkeys...cause I don't know jack about turkeys.