I have had many animal deaths since I have lived. Mom has always loved animals and so I have had deaths to go along with that.
I have had I think 5 guinea pigs, and 2 cats.

Very sad. I have had Oreo first. He was the first ever guinea pig death that I have had in my lifetime. He looked like an oreo cookie. He was black and white and it was mixed together. He was sweet and I loved him very much and it was sad when he died. He had died of a bladder stone and it was heartbreaking...
The second was Twinkle. She was always a very fragile pig, and she died of a stone also, just like Oreo. We had to hand-feed her, and be careful when we picked her up to put her in our laps and could only pick her up occasionally.
The third was Boris and Nellie. They both went down at the same time and was really bad with 2 guinea pigs in sickness and not doing well at the same time together. They were the best of friends and helped each other out at times of need. Boris had also been fragile, and after Oreo died him and his wife Natasha had come into the guinea pig family. Natasha is 8 years old and is still doing well, but shes fragile right now. But, Boris had had trouble breathing and couldn't swallow his food very well, and then his partner and friend Nellie (my favorite guinea pig before she died) had a tumor in her lung.
The most recent guinea pig that died was Roxie. She came in with Belle and Belle now lives with Natasha in one cage just 2 friends. Roxie had a stomach twist and its called a balop? (I dont know how to spell that really) but we couldn't let her suffer anymore and had to put her down...
All these deaths were very disappointing and everytime an animal dies, whether cat, dog, guinea pig, etc. we bury them in the backyard by the woods and put stones over them... We love them still and will always keep them in our hearts for eternity..