I got my female almost breeding size bumblebee from a reptile specialty store. Yes, I made sure she's a female.
When I picked her up she was freezing. She's finally filling out. They had her eating 2 adult mice once every two weeks. I haven't weighed her lately, but last time I did she was only about 20g away from being 1500g.
What gets me laughing is how they're selling HET CLOWNS. I don't know, but I wouldn't buy a het off of a pet store.