Problem with eggs

Sorry folks that I only seem to be on here at the moment when I've got a problem but what with one thing (OH and his 2nd total knee replacement - he's doing quite well now) & another, time just seems to fly passed, anyway back to the current problem with the chooks -
all seem to appear healthy but one of them has laid suspect eggs recently i.e. when cracked open the egg has dark/black speck/s in it (i've flushed them to be safe) but cracked one today & it appeared to have a small black 'wormy' type thing in it (that egg also got flushed away) the remaining girls eggs seem to be be ok.
The BIG question is - should we be very worried? and can it be treated if there is something wrong?  Also what could it be, please if any one knows?
Many thanks in advance... ....

thanks joyfull, the wormy thing was in the albumen same as the other bits in previous eggs but if it should happen again, will be sure ti take piccies & post but hopefully won't have to, fingers crossed.