Still Squared Off After Birth

[daizeUK]

My wagtail had her second batch of fry over a week ago now but she still looks HUGE.  It was a surprise to find three of her fry in the tank as otherwise I'd have thought she still looks pregnant.
 
She is acting and eating normally so I haven't been too worried about her.  Is this normal?

 

[helterskelter]

In healthy livebearers most females will be producing egg's while the fry are developing, this is why they stay quite large.

 

[daizeUK]

Last time she went slim after dropping fry though.  This time she's still squared like she never gave birth.
 
There was another fry in the tank this morning, same size as the other three.  I assume it's been hiding in the tank so I hadn't seen it until now.  They're a full two weeks old now and mum still looks the same.  I was worried there might be more fry stuck inside her but she's showing no unusual signs of distress.