Blackbird nest tragedy

So, I've been keeping a watchful eye on a blackbird couple for over a month now. They've successfully built their own nest in the front garden hedge and were always seen popping out for food and water. 

Unfortunately, after being away for a few days; I've not seen any sign of the female. The male blackbird is visiting regularly (I think it's the same one) but no sign of Mrs B. 

I decided to have a sly peek into a hole of the bush, only to find two chicks and an unhatched egg within the nest. Unfortunately the chicks weren't moving, even after a gentle niggle of the resting branches to check. 

Am I right in assuming something has happened to the mother? Or is this looking like she has abandoned the nest? 

Just to be clear, my wife has seen two cats lurking in the garden on a few occasions. Add this with the other visiting birds such as sparrows and starlings; it may have been too much for her to bare.