Before I started ordering from a local supplier, I was ordering from
Layne Labs.
You can order as few as 10 mice at a time from them.
They also sell rabbits, quail, chicks and guinea pigs.
I learned about them through a friend. They provide feeders for zoos, wildlife rehabilitators, universities, and pet industry.
Their quality has always been great, and if they made a mistake on the order (didn't happen often) they more than made up for it for me.
I can get orders on a quicker turn around than any online order, so that is why I started going with the local supplier.