Like Star, for various reasons, my DD ended up at 4 schools by the time she was 6. It wasn't that the moves CAUSED her reading issues, but that her reading issues (and the general lack of support in the first school for SEN) that caused the moves, that and forced house moves.
School one told me in front of DD that she was 'too stupid to learn her letters'. Would you send your DD to a school where her class teacher was calling her stupid to her face, in front of the whole class?!
I moved her to a school an hour's bus journey away, as it was the only school with spaces that would take a DC with SEN.
I had two younger DC's, and the 4 hrs a day on the bus was impinging on THEIR development. So when a place came up at a local school, I moved her.
A term and a half later, I was moved to a new house by the Council, as my flat was condemned.
So DD HAD to change school again, as the other one was I reachable by public transport due to my job at the time. (I was working FT nights, getting in, then leaving straight away for the school run as my partner at the time had to leave for work as soon as I got in the door!)
It was a shame, but she already HAD the reading issues BEFORE the first move.