onions being eaten

Last year I had problems with onions being eaten.
There were large pieces missing from bulbs and also leaves going missing.
I did have some onions over-wintering in a netted area, which lost their leaves last week, so it can't be birds.
Would rats do this or squirrels?
I have never had this problem before and am wondering if it will be worth growing onions this year.

The attrition rate this year for my over wintering onion shoots has also taken a hit. They're netted against arial assault, but not well, and pigeons can walk in through the odd opening. I've also seen a marauding bunch of pheasants hanging around this year, but they would have probably decimated them. Could be voles or maybe wabbits, but whatever, I must take onion netting as seriously as I do brassicas. In the past I only netted for a few weeks until the onions got away.
But as always, the best defence has again been to plant more than I need. Irritating though.

The broad beans are doing great though, but for the first time they're under enviromesh. Pristine they are.

I have had the same thing this year for the first time was well. Based on the protection I think for me its mice or rats. Whilst we have squirrels  its 50 yards to the nearest tree plus no sign of digging which is what they usually do.