Female Guppy / No Fry???

[motherof6]

I have a female Guppy who I consider quite small. She gave birth the beginning of January to 15 fry. Since then she has not had another batch or even looks like she might be pregnant. She seems very healthy why would she not be having more fry?

Here are som epics of her:
Pic of Eve

Guppy Pics Thread

She is by the pot in the first pic in this thread.