It happens to mine every year too but only to the small daffs. It also happens to some snowdrops. It's disappointing isn't it so I can empathise. I always put it down to slugs but I could be wrong. Gardeners on here will have more idea.

I have caught those keeled slugs munching daff and snowdrops so they are definitely the culprits in my garden and even between the snow they have been out and active, grr.

agree with keeled slugs , little black type as soon as we get a couple of warm days up they come out the soil ...

Thank you, slugs it must be!