Its always better to feed them in their enclosure from what I've heard and experienced, just less stressful for you and the snake and you don't have to risk regurgitation when placing them back in their home. As for the new ones how long have you had them for? Could their reason for not eating be from not being comfortable yet? I know there are some ball pythons that will refuse to eat frozen thawed but sense they were on it before that shouldn't be a problem. I have always had success using a similar thawing method that was stated earlier, I leave it in the fridge all morning then place it in a bowl of luke warm water for about an hour then use a hair dryer to warm it up. Some snakes are picky with the way you offer the food, some of the methods people use are having it do a little zombie dance wiggling the mouse around of the tongs while holding it by the back legs or tail, tapping the snake gently on the snoot with the mouse, or simply dropping it into the enclosure and the snake will come out and eat it on its own. There are plenty other methods but those are the most common I believe and the ones I personally have had success with.
Just as a side note did you make or buy your racks? And where did you get or what references did you use to make them? Sorry I've just been looking into to ranks myself and I like the look of yours ^-^
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