Early morning visitor

It's exactly midnight in the UK, 1:00am here in Germany. This cat is not one of our four but has been living somewhere on our property for months probably in the horse stable. He/she comes several times a day to feed at the living room door. Tonight managed to get her to put a foot in the door (at +2°C, it's warm enough to leave door open for a while). Felt very sorry when it was -17°C last week but she's very shy & it doesn't help that our cats & dogs chase her away. Tonight Luna was very good & sat at my side & just watched, I think hoping some food would be left over but no chance.
She looks in good shape, I hope not because she is pregnant. Have just read that a cat is preganant for 9 weeks and as all our cats are neutered/sterilised she probably isn't. Must be the food - no animal has ever starved on our property, they stand a far higher risk of dying from obesity.