Well...not necessarily, the way I'm looking at it. The dam had a healthy immune system prior to ingesting something that could have toxins. After ingesting it would be in her body, and in her cells. As her cells reproduce & die & are replaced, she would eventually get back to a healthy body once again. (Although she may have a weakened immune system.) Her first litter of kits would get the first "blast" of issues since toxins were still heavily in her system & cells, the second would be less problematic but possibly still have some issues because the immediate toxins would have left her system and secondary impact on cells would be working its way out, and possibly third and consequent liters would be back to her norm as her body repairs itself. I agree with you on that theory.
Now, as far as the offspring: the first gen would get a "blast" of immediate toxins in utero which would impact them and they'd need to detox after being born if it didn't impact their development--but it is also possible that those same toxins may have altered their very genetics and/or caused minor deformities or issues in internal and reproductive organs that are not visible. This wouldn't then be a matter of letting their bodies heal themselves, as was the case of their mother, but the possible toxicity may have altered their very structure. (Their life supply of eggs that they are born with could be impacted as well, which might mean all their eggs may be more likely to be defective.) That would mean the odd issues in the kits might be their norm. They may be formed in such a way that issues aren't visually noticeable, but that they may have distortions in their very genes--and in that case giving them time to work it out won't make a difference. I suspect they are possibly "not right".
I'd unknowingly been exposed to a heavy dose of pesticides when I was a young adult. While I looked seemingly healthy and med tests at the time didn't reveal measurable toxin levels, I started to display asthma-like reactions and other health issues during heavy traffic times or near polluted areas, or even if I smelled air fresheners, household cleaners or was too near someone wearing perfumes I moved from the area and to another state entirely and went on a very "clean" diet and lifestyle. It took about 7 years before I quit experiencing any immediate symptoms and felt close to normal (although to this day my immune system isn't strong, and I will sometimes break out in hives from being near to toxins (something as simple as even filling a car tank with gas) or natural irritant when I am under stress--basically, anything that puts extra stress on my body and that never was even a noticeable issue to me prior to the situation.) Putting that out there because exposure to toxins can really have a strong impact on some living creatures and you'd never know it from looking at them.
Not sure what I'd do about sending the kits on as woolers. Other folks should have better input on that than me since I just raise meat mutts, and I'm with you in thinking I wouldn't eat these, even if it's just an odd chance.
oh--sorry, katiebear beat me to the punch & said all that but in a much cleaner and clearer way than I did. I agree with her points.