We have a pair of ring necked doves that have made a nest in our porch - they have 2 and seem to alternate between them when laying their eggs. Sadly, I think a fox has got one of the parents yesterday and now both chicks are sat in the nest. They have

We have a pair of ring necked doves that have made a nest in our porch - they have 2 nests and seem to alternate between them when laying their eggs. Sadly, I think a fox has got one of the parents yesterday and now both chicks are sat in the nest. They are quite well established but I haven’t seen the other parent coming to feed them. I have seen the bird on the roof of our barn watching over them. 
should I just let nature take its course or should I try and do something (I’m not sure what) - I could cry looking at them both Sat in the nest.