I'd be more concerned about the volume of muscle than the size of the belly. The belly also looks bigger because she has a little wool on and she just doesn't have the thickness of the top end lambs today. Take your pictures and put them side to side with some pictures of lambs in the OnLineSheepShow.com, ewe lamb classes 5-11 months. As a March ewe, she's in that age group.
- She's lean, probably will show as one of the leanest lambs in the class if you showed her today. Fat makes "white muscle". Lot's of judges are impressed by the thickness of fat lambs, particularly if the fat is a hard fat that you get from show feeds and not just corn.
- IMO she's finer boned than most current top end show lambs. She doesn't have the shag that makes that bigger boned illusion. You can fit the legs like a steer, (card the hair out, spray to get it to stay), that helps a lot
- Isometric exercises and windsprints build short muscles which are what win shows these days (think sprinter). Long flat muscles are what long distance runners have. Which does she remind you more of?
- IMO, the reverse feeding program, (more feed, more fat, with muscle building supplement such as champion drive) and a every 2nd or 3rd day intense muscle building exercise program will help make the lamb more competitive.
- Longer running can help with weight control, lambs can be held a long time if weighed weekly and their feed and exercise program tweaked.
- Belly size can be influenced on show day a lot with feed quantity and helping the lambs belch.
- She's not looking very "broody" to me yet. Problem with showing ewe lambs at ages older than somewhere around 8 months is they start looking like brood ewes. Wethers don't do that.
- All that said, it's been a while since I saw a lamb with good muscling, correct structure, good bone that was shown well lose to a lamb lacking any of those items that had a smaller belly.
