From the Downton Abbey companion book by Julian Fellowes:
"Daisy is treated as an inconsequential junior by the other servants. 'She would have had a tough childhood', says Julian Fellowes, 'so low in class that there is a greater distance between her and Carson than there is between him and Lord Grantham. They're from the functioning upper end of the scale and she's from the dysfunctional lower end.' In fact, she would have been almost rescued by Mrs Patmore. 'We know she has hardly any family at all and Mrs Patmore may have taken pity on her and brought her into the house,' says Julian."
Was he implying sexual abuse? In one episode Daisy herself said to William "Never in all my childhood did I have someone I could always trust". Doesn't that statement sort of reek of sexual abuse?
And we recently learned that Anna was sexually abused as a child. She probably came from a better family than Daisy and yet even she was abused; doesn't that make it more likely that Daisy was abused as well, since she came from a worse, poorer family?