Do anyone have any ideas on what is happening to my Egyptian Walking Onions?

Last year I planted Egyptian Walking Onions. They were doing great, showed no signs of distress and all of a sudden just disappeared.

This year in Febuary I planted about 15 bulbs. They quickly sprouted. I just checked and now I only have 3 plants. They are in the middle row surrounded by 2 rows of another type of onion. The other type of onion is not having any problems in that area.