Adorable Foster Kittens Play Fighting

I fostered these 3 adorable kittens and their mom from a local cat rescue. The playing and fighting kittens are around 8 weeks old. Almost all of them were adopted into wonderful forever homes. Sadly the white and tabby coloured kitten I named Birch was put to sleep – he had had these bursts of energy but would then fall into an intensely lethargic state. X-ray showed he had blood in his stomach along with a mass that the vet said was either tumour or cancer. He was most likely born with it and far too youn