I don't know if anyone else has this problem this year but my rhubarb stalks are thin and spindly.I don't know if it is the weather conditions causing it or it is time to split it.I soak it at least once a week and it had a good mulch on it earlier in the year of homemade compost.Rhubarb on nearby plots have the usual mixture of thick and thin stalks,in various stages of growing?
The crowns have been in the same place for over 20years so it may be time to split/renew them, the point is the crowns are in the "right"place in the allotment so I in a bit of a quandry as to where to move them to or can I lift them,split them,dig over and plant them in the same place;I seem remember reading that this wasn't recommended.

I've seen rhubarb go spindly if it is growing in shade. Has the site become shady when it didn't used to be? (a tree nearby growing larger, perhaps). I've not split my rhubarb in 30 years and the stems are still thick (and it has still never flowered, which is only a good thing). Now I think about it, have you been removing the flowers?

You can replant it in the same place. But if you are going to dig it up, you might as well split it and try a piece in another part of your plot where results may be different. I don't recommend replanting at this time of the year, only when it is dormant.

Evening Felix,
No,nothing is in the way to cast shade on the rhubarb and it has only flowered twice to my knowledge and both times a single stalk which was whipped off as soon as I noticed it.I'll see how it goes through the rest of season and then decide what to do with it.

Evening Snooky, just a thought, i was wondering whether it cropped very heavily or, could you have over picked it last year?

If this might have been the case, it might just be having a rest this year and be back to full strength next season.