My (let me qualify - my son's) bp has been eating frozen mice since we got him. Frozen is good with me. Anyway, for the first 1.5 years he has been finicky at best. Would eat well for a month, then not eat at all for a couple. When I switched to 'fresh' frozen mice - which I did under protest... The store didn't sell frozen anymore so we did the deed ourself (YUK)... he ate great. I guess liked the freshnes. Did well every week for 5 or 6. Then went back for more and they had frozen already - so of course I bought those. And, of course he didn't like. Tried 2 weeks in a row and no luck. SO I send hubby to buy 'fresh' small adult mice so we can make 'Squeezer' happy. Stuck those little boys in the freezer and just went to take one out for feeding and UGH he bought rats instead. And they are big! Like almost twice the size of the mice. What a shock that was. Have wondered if little Squeezer needed more than those small adults for a while .... how do you know? And, now wondering if I should try to feed him the rat.... Don't know why I started with mice -just did. What is the difference and obviously at some point you have to switch because of size. Should I try the rat? If it is too big will he just not eat? Will I stress him out really bad? Hmmmm - know someone here can help. Thanks! Squeezer's mom.