Hookworm prevention questions

[Sundrop]

Was wondering about how I can best prevent hookworm infestation in my two older greyhounds since we just found out today that new adoptee has them. She's on Dr. Ng's "triple combination" protocol and I've been reading a lot here about treatments and issues (very disheartening, I must say) - but my bigger questions are around how to protect my two negative greyhounds. 

Unfortunately we weren't aware this was even an issue, so they ran around the yard together for almost two weeks - we have someone clean the yard once per week, and they often "go" on walks, so the yard has never been an issue. But...now we are concerned. I know that cleaning up right away is #1 (even though we can't do the "paper plate" thing of following her around since she's pretty skittish and she tried to get away from me when I followed her around with a baggie today, lol).

Both existing greys are on Heartguard Plus and vet explained that even if they did get infected, it wouldn't really be the same thing since it wouldn't be chronic infestation that ended up in tissues and re-infected intermittently, and that the HG+ should protect them and kill any adults right away. Is this the case?

Does cleaning feet immediately after being in the yard help?

I've read the adults and eggs can't live through a hard freeze - but has anyone tried using one of those "poop freezing" sprays to kill them? We live in NC, so hot & humid weather is on the way - but if we pick up right away and then freeze whatever remains in the grass with the spray... might that work? I've read there is no proven way of treating yards - is that the case? I honestly don't care if I kill the grass, I just want to kill the hooks.

Does anyone know how long they can live in soil? I guess our yard is infested now, which just sucks since we didn't know, but whatever - we have to deal with it. Can we do anything at all? Spray with bleach? Wondercide? Anything? Or... are we just waiting for a hard freeze this winter?

Finally, how many of you have dealt with a new adoptee "infecting" your existing greys (or other dogs)? Are they easier to treat as my vet suggested? Is there anything else I can to help our new girl and our existing two? Still researching her treatment, but hoping to get a crash course in protecting the other two. Should we section off our yard and keep them separated? Buy them booties (which would be super funny)? Any tips or knowledge would be greatly appreciated! 

Edited April 16, 2021 by Sundrop
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[Sundrop]

Sorry, follow up question here about my new adoptee's protocol, as I do not think it is sufficient after reading so many threads here. Is this enough? Vet seems open to trying new things, but I want to be clear and also see if there is documentation on it (she sent me home with "Hookworms and Racing Greyhounds" data Oct 2019 by Dr Ng) to share with her. The Prison Protocol link I saw in previous threads is a dead link now.

We have 3 days of Panacur granules (started today)
Today we also gave her Strongid (only got one vial of this)
Today we also applied Advantage Multi - we are to apply this every 2 weeks for 3 applications, then switch to monthly
Re-test her in 6 months

That's it. Is that correct for initial treatment? Thanks!

[cleptogrey]

Speak with your vet or do some major research as per cleaning the yard for eggs. DE( spelling is incorrect but Google will find it diametheous earth ) food grade should that care of the eggs/larva. It dehydrates and cuts the exoskeleton of the worms with out destroying your yard.