+1 to the hopper mouse suggestion. I picked up a 60 gram pastel last summer and she would only start on hopper mice for me. After her first couple, I started giving her two hoppers per feeding. It didn't take long for her to be on adult mice and she switched to rats without any problem. She's now up over 1000 grams.

I picked up a 55 gram lesser bee male at a show a few weeks ago. I tried him on an ASF hopper and a rat pink and he wasn't interested in either. I went to the store, got him a hopper mouse and he nailed it instantly. He had two feedings of single hoppers and took his first double hopper meal for me this weekend.

Once you get them eating something it will be less stressful trying to switch to rats...