Do bulky nappies affect development?

No problems here. DD1 was early to roll and crawl I think and walked at 11 months. DD2 started rolling at 3 months. I wouldn't worry :)

Thanks for the words of reassurance ladies. After quite a few days in disposables due to our recent wonderfully wet weather, my DS still doesn't roll at all, so it must just be him being a lazy baby. He can sit a bit better in the 'sposies but I still have to sit within reaching distance of him so I might as well do it with him in cloth nappies. I'm feeling creative at the moment so I might try and make my own.

my bubba isnt rolling yet either shes 8 months old and shes only just sitting up :)

My third bub was exclusively cloth and he was crawling at 6mths and walking at 9 :o

Yep, as MIL pointed out to me years ago, cloth can be good for the hips (displasia runs in their family).
DD3 has been in cloth full time since birth & was standing at 7.5 months. All other milestones reached around average, maybe slightly earlier.

I walked at 10 months in my clothie bum ;)

ETA - 90% of our stash is itti's :)