Green acid, I have a suggestion that might help you out. Try scenting the smallest wen rat you can find in mouse soild bedding. I have a female 1400 gram pastel who will not touch a rat and after doing this scenting for a month of feeding, she switched to wen rats. After getting a good 2 months of wen rats weekly in her I now have her pounding sm rats weekly.
Before I switched her, she might have grown 100 grams in 3 months, now she's growing at about 100 grams every month to month and a half. Her sister on the other hand will only take mice or mouse scented live rats, i don't really like feeding live so i give her 5 lg mice every week, she might grow 100 grams every two months at best. She was right at 1000 grams in dec before she went of feed and since april when she came back on feed she has gotting up to 1200 grams. Now she did loose about 200 grams in the fasting period.
Try this out and hopefully it will help you.