Eggs laid

[Maddy]

Hello folks,
Besides my tortoises I have 2 turtles, one common musk, one razor back, I've had them for approx 6 years, they've always been very happy together and today 3 eggs have appeared, quite large, so I imagine the razor back has laid them.
I haven't seen any change in behaviour, the only thing I changed was an upgrade to a super duper external filter about 4 months ago.
can anyone advise if they could be fertile or do they just lay out of instinct.
And what I need to do now.
Many thanks in anticipation
Maddy