I'm wondering if she has waterbelly(ascites).
Meat would be on the breast(blue circle).
Ascites would be in the abdomen(red circle).
Probably should check her crop function and poops.......
When I have a bird that is acting off I isolate bird in a wire cage within the coop for a day or...
Are you sure it's 'meat'?
Is it solid or squishy like a water balloon?
Is it in front her her legs or behind them and closer to her vent?
Compare her belly to other birds.
How do you know, are you weighing her or is her belly swollen?
Birds that are ill can be ostracized to a lower ranking as they may be trying to drum her out of the flock.
Low birds are the mostly likely to beat up any newcomers.
How old is Ivory?
How did you add the chicks?