Mine did the same thing 2 versions ago (1.5.4) and I was also over 1000 items unclaimed... Then 1.5.5 came out and I downloaded the original game from the app store. The issue continued to happen but not quite as much, I was atleast able to get in to my unclaimed items and start clearing some of them out. I had to take them, put them in my inventory, then delete them. Once I knocked my items down to around 500 I noticed the speed of the game was less glitchy and less restarts. Got down around 350 and the game worked fine like it should. This was about a 5 hour process between the game shutting down on me but yes, that is my best guess. Currently on 1.5.6 non-jailed version and its working like a charm now!