Yuo could probably get a lot of info on this below, but I will go ahead and go over it.
I have found that hairless food itemss go down better and stay down. I'm not saying I am agianst using food with hair. It is just fine but it is just a preference on my part. Simply scent the prey item with fish. Mash the fish all up and rub it all over the thing. ANother way I ahve gotten my pikier ones to eat a hopper mouse that I pulled the hide off the head and upper torso (so to speak) and pulled it down half the body,sort of undressing it. Keep the skin on it but just pull it down making what would normally be the inside of the skin on the outside. Sort of turning the mauses clothes inside out. I only pull it down half way down the boddy and therefore you have no exposed fur. I have done that wiht several of mine that would not swallow an object with fur. Make rue you scent real good this way.
If anyoen breeds rabbits in your area, you can get some baby rabbits to feed to your larger Nerodia. I am trying to start a colony of hairless rats right now, that way I do not have to mess with fur at all. With babies, I can use piny mice. When they graduate form pinkies and owuld normal go to fuzzies then I can go to pinky rats. The larger rats until they can handle baby rabbits. I think fish should be thrwon in too because I think it is always good to have a varied diet. What state are you from? Lets see some pics of those diamond backs. I gues I'm done?
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Justin