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They are probably bored shitless and overwhelmed. Take them somewhere everyday in the holidays and get them to do some specific jobs before going, like your 11 year old can fold some washing, your 8 year olds can do the dishes and your 4 year old can wipe the table. Keep the jobs simple and put a hurry on it, like quick we have 20 minutes before we leave and we HAVE to do these jobs before we go! Make it sound urgent, don't give them time to think about it and whinge.
My kids are similar ages. I find that they get overwhelmed with the mess and just don't know where to start so they don't bother. For me taking one child at a time to their room and literally sitting down with them and pointing to a toy "pick that up" pointing to where you want them to put it "put it there" and just showing them how to clean up, seemed to help. It's time consuming initially and takes forever the first few times, but after a few times you just go in and start them off pointing to a few things to show them how to start, then asking them to keep going and they'll do it on their own.
You and I know what we mean by "clean up" but as silly as it sounds, kids don't actually know HOW to clean up, unless you show them. And the bigger the mess the more overwhelmed they get.