E.
In my preschool classes I have seen this sort of think a lot. Either they act up prior to going to one parent's, or they act up after coming home, or both. I would suggest definitely talking to the Dad, but realize in doing so you may be opening a can of worms. He may want to persue a different custody aggrement or whatever. Anyway, I find that the issue deep inside is usually a problem of the kids feeling a lack of control over what happens. Many times, on these problem days I let the child make as many choices as possible...what they eat, what they do, how they do it. But you still have to have boundaries, and if they cross the line, they lose priviledges. This is usually another issue they have...discipline helps them feel in control. They are lucky to have a sitter that caes so much about them. It sounds like they need all the TLC they can get!!