Eight cats and kittens were found abandoned in a Norfolk field.
The cats were discovered by a farmer in Didlington, near Mundford, at around 6.30pm on Tuesday, October 17.
The animals were passed into the care of Breckland Cats Protection.
Alison Lardner, a volunteer for the organisation, said: "The cats wouldn't have survived if they hadn't been found.
"This is as bad as it gets, it breaks my heart.
"We think they were being kept in very bad conditions."
Ms Lardner says the cats are very thin and were found with matted coats.
They were sealed inside crates which were secured with zip ties.
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She added: "This is not an isolated incident.
"This is the worst year ever for rehoming, we're completely overrun with cats needing help.
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"It's a very difficult time."
She says escalating costs and a shortage of potential homes are among the factors that are causing breeders to abandon animals in this way.
The cats are currently waiting to be rehomed at Breckland and Ely Cats Protection and will receive veterinary treatment next week.
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