I think that points to an egg/eggs (most come in clutches, 1 each 24 hours or so, but Noodles only ever makes 1 at a time for some very odd reason). If you knew when the weight gain started, you would have a better guess of when the eggs should come out, but you basically have roughly 48 hours or so from the time of formation to expulsion of the egg. This isn't exact, but it can be an indicator of egg binding vs just egg laying. Larger or smaller poops do occur in egg bound birds but it may not be that...Heck, even just a bird laying a normal egg can show some of those signs.
I would make sure you get him/her checked though, as that is a massive weight gain if it isn't a clutch of eggs and because you aren't sure if this is binding or just laying (but it's super important to know). The first time my female cockatoo made an egg, it was years after she was sexually mature and she did need injections to help her pass it.
Feeling the abdomen of a hormonal parrot is very sexy to them, so try to avoid it, but you can try to quickly feel for a bulge ifyou are familiar with how that area normally feels. That having been said, they sometimes form high and cannot be felt, even by avian vets. An x ray would tell you a lot.
Make sure you crack down on those hormonal triggers (10 hours sleep, head and neck only, no shadowy spaces etc) and if an egg comes out, DO NOT remove it until your bird totally loses interest. You can buy really convincing dummy eggs online at dummyeggs.com
http://dummyeggs.com/ (if you remove an egg before that time, or fail to swap it with a convincing dummy, you reset the cycle and they will make more).