Thats sad and all too common. Ive only rehomed two animals. Guinea pigs that i ended up being allergic to and couldnt breath. All my atshma meds and allergy meds couldnt fix it so i found them a good home. And a lab that was extremly high strung and was unhappy and bored at our house and needed a family that was more active and would give him a task to do to occupy him . he is thriving with them and theyve had him 6 years now. If not for it benefitting him and the allergys theyd still be here.When I volunteered in a bird shelter I saw that all the time. It's sad . That's like signing off your child off for adoption whenever they did something you don't like.