This isn’t quite normal, usually at these facilities in the case of 15, 22, and 20 especially show that the workers are not carrying out proper regular assessment and that the criteria for euthanasia for excessive suffering looks to be far to high. I only know the case of how this kind if testing is handled with mice (from my partner, and in germany) and all three of these cases would have been euthanized much earlier, not left to live on for a year or even days. As usual with Musk, he tries to cut corners and it only ends up hurting people and in this case animals unecessarily.