I have identical DTS (girls) who, whilst being the youngest in the year (late Aug birthdays), settled well into reception and have remained happy since. They go to a lovely one form entry village school and haven't had any problems making friends, teacher has remarked from the beginning that they've settled well, are v confident & bright, are doing well academically, etc.
Over the last 2 or 3 weeks DT2 (the slightly more confident, yet also more people-pleasing one) has been pinching, hitting, kicking other children in her class (for v minor things they have done to her - written on her drawing, pushed in front of her in a queue). When she was little, she was prone to bite her sister from time to time, and still does lash out occasionally when angry, but has never, ever touched another child at pre-school or until now in reception. We were told that she kicked a year 5 girl at playtime the other day and spat at one of her classmates 
. This kind of behaviour is really out of character for her, and it's making me feel really upset - both for her at school and the thought of her being labelled the 'naughty girl'. I've been in to speak to her teacher and we're trying a sticker chart, with a treat at the weekend if she gets all her stickers but she's already missing 4 this week (one given each morning & afternoon), and so is likely to miss her dance class tomorrow if she can't earn them back today.
(As an aside, her twin sister is also doing the chart to make things fair, and has got all her stickers so far this week. We've never had an instance of bad behaviour from her at school.)
We've had lots of chats at home about how people feel when they've been hit, how we must have kind hands, and be caring to our friends and she knows all the right answers when we talk about it, but then goes and lashes out at school. Incidentally, I've been making a real point of praising good behavior at home this week, and she has been an absolute angel - no agression, kind to her sisters, etc. So it is just happening at school
I've been racking my brain as to what could be causing this behaviour and I'm wondering whether it might be because as a twin, she is always labelled as such, "DT1's sister" "DT1 & DT2", and when she misbehaves she is actually carving out a separate identity for herself as the naughty one. I help in the class occasionally and noticed that a few of the other children 'tell on her' quite a bit, but she doesn't seem to mind. She doesn't seem to mind sitting out of activities either, and I wonder whether it's because she gets attention because of it?
Anyway, I'm waffling now. I just wondered whether anyone had any ideas about how I can turn this around and help her to become recognised in her class as being good at something (thereby carving out a positive identity), rather than relaxing into the role of the naughty one.
Thanks in advance - will post this in Multiple Births too....