Feeder rats with lice?

I found that two frozen rats out of a pack of twelve that I ordered from a local seller appeared to be infested with lice, so I contacted the seller about it. I've ordered from them several times and this is the first time I've encountered anything like this. Usually their frozen feeders are clean and good quality. They told me that their rats are treated for parasites twice annually, but that the lice don't always fall off after treatment, and that once dead and frozen the lice are harmless. I also asked if the parasite treatment they use is toxic to snakes that eat the rodents and they assured me it wasn't.

I just wanted to confirm if this all sounds right or not and if I should buy from this seller again? Is it normal to need to treat breeding colonies of feeder rodents for parasites, and are rodents that have been infested with and treated for parasites still safe for snakes to eat?

Personally I would find someone else, the fact that he treats for external parasites twice a year and still have issues shows there is a problem, I have been breeding mice and rats for 13 years now and the only time I ever treated rodents for parasites is when I added new blood. (only the new animals were treated and this was done while they were quarantined)

And while I may not produce as many as your supplier I still produce several thousands a year.

As for feeding feeders it depends how they were treated and how long after treatment they were euthanized and frozen.

I've been raising rodents for several decades & haven't had that problem, not even when I had many more than I do now & supplied others .
I'd find another supplier too, & I'm not sure I'd trust the safety (for my snakes) of whatever they treated the rodents with. Ish! :confusd:

Rats are cheap, I'd toss the whole lot and buy from another supplier, no way I'd risk my animals health to save a few bucks, even a couple hundred bucks.

Thanks for the feedback everyone, I'll throw out the rats and look for a new supplier.