Rats get frighten more than Mice>>

[reptilesalonica]

I think that it is strange...
I keep my feeders in one room in the appartment.
I breed mice 2 years ago. All my mice (except the hoppers) are quite tame and i can hold them in my hands. I have close to 200 feeder mice and none of them ever bite me, plus the thing that i don't use forceps, just my hands.
One month ago i've got the 1st rat breeders (1.4 hoppers).
Until now i observe that whenever i get in the feeder room they get very frightened. I always treat my feeder rodents with care and with ease moves when i am cleaning their cages or when i feed and watering them.
I treat them just like they were pet rodents.
This fact, plus that i enter the feeder room daily and i spent 3 hours in it, every 2 days, contradicts with the frightened behaviour pf the rats.
One more is that it is known that rats don't get frightened that easy as mice...
Any suggestions?
~Greg~