Very interesting thanks! Your google fu is strong
By my estimation, if one chicken ate the
whole lot of slug tape, they could have got up to 3g of pure copper in their crop. The top level used in the feed study was dosed at 800mg/kg feed, which would equate to the our bird absorbing the whole 3g over about a 4 week period, assuming that it still eats 150g feed per day and there is negligible additional copper in the feed (we use organic pellets). As we've been away for 3 weeks and the little lump in the crop is still there, this rate of absorbtion is probably a realistic worse case. So as long as the bird can tolerate it and it is not affecting digestion etc, it can probably live with it. When removed from exposure, levels dropped back although some birds exhibited liver damage.
Regarding the eggs, the interesting finding is that "the copper content of egg reached a maximum at 400 mg/kg dietary copper". So about 25 mg per egg. A quick google suggests that the RDA of copper is 1-5 mg for adults, and
toxicity to humans generally involves daily doses of >15 mg. An
Australian public health guidance note says "The provisional maximum tolerable daily intake for copper is 0.5 mg/Kg body weight (Joint Expert Committee on Food Contaminants and Additives), which corresponds to 30 mg of copper per day for an adult weighing 60 Kg."
In theory you could, if thirsty, get 10mg per day from drinking tap water (2 mg per L permissible standard) and another 15mg if you dined on veal liver....
So as a precaution we really should avoid the eggs until it is resolved.