Where I went to college, there was a lab with 3,000 dogs in it. All of them were being used for scientific study. They couldn’t even let them outside because they didn’t know if the dogs would get sick (“contaminated”) and ruin the study. The dogs have been bred to have a heart defect. They were all euthanized at various stages to see how the defect was progressing. Many dogs did’t even have the defect but were put down and dissected anyway.