Ball pythons are very sweet things but notoriously difficult to feed. He hasnt ever even hissed at me in 8 years! They like to go off feed on fast for long periods of time tho, ive heard of over a yr. If you always fed them albino mice and the store switches breeders so u have black n white ones? They wont eat it 

 if its a bigger change than that dont even bother til hes starving 

 those rat snakes can be aggresive to keep captive but the gophers or regionally here bulls i mentioned earlier are Super aggresive ive seen one guy keep a pair and everytime u went near em they wanted to strike the glass til he moved em to an opaque enclosure. Ive also had chameleons and bearded dragons and fed them occasional mice.