I've had a female around that size go off feed for 8 months and I tried every size color and rat,asf and mouse live,Ft,pk untill I find what it may be sometimes it's wierd and a little tuna can juice works,change of enclosure, hides,a little flucuation in temps crumpled newspaper.
Bps are known to be picky eaters and go on fasts... But sometimes a little adjustment can make all the difference.