Oh Oz, how I've missed being contradicted (or is that contraindicated) by you. Its so refreshing. Just kidding.
I have to stand by my use of u100's, chickie skin is so delicate, I like a more delicate needle. You're only injecting under the skin, you don't need to jam it in there, the U100's slide right in there like the skin isn't even there and there is little to no bruising.
I can definitely say that the diluent says on the bottle to store at room temp (as long as its below 80F), but the vaccine needs to be refrigerated until a little bit before use.
I make up my vaccine, load up all of my u100's and then either move the chicks from one box to another or use bands to indicate who's been done, but the box thing goes faster. I have to disagree with reusing needles. They dull so quickly, you cause more pain as each one is done.
The vet I used to work for would have us draw up a vaccine with one needle and then toss that needle so that she could administer the vac with a fresh, sharp needle. That's how quickly they dull. I will reuse them once, but I definitely alcohol the needle before reusing it. U100's are so cheap, its worth it to get as many as you need and only use them once.