Feeding Rats

[Will]

In the next few weeks, I'm gonna need more rodents, and had a couple questions for those willing to answer them. I'm planning on just getting one big order to last me(hopefully) until this time next year.

First, what are the rough size comparisons between mice and rats...? By that, I mean, a Rat Fuzzy would be comparable in size to a (insert mouse size here). I've never actually seen a rat before, so when someone says "Small Rat, Medium Rat" I've got no clue how 'small' or how 'medium' that rat is.

Also, which prey item is considered healthier...? A full grown mouse or a less developed, but larger rat...? It seems that alot of people here seem to feed rats over mice and was just wondering if there was a reason for this. If one proves healthier or more beneficial than the other, I'd obviously go with the better choice.

Third, all my snakes are well established on mice, and as far as I know, have eaten them exclusively. Is it at all difficult to switch them over...? Knowing their tendancies to be eating machines, I don't expect this to be too difficult.

Lastly, does anyone know where to order some rats at a good price in or near Edmonton...? I've heard there are breeders in BC and Sask, but need some contact info. You can PM me that last answer if you prefer.

Thanks.