Three kittens were found in a pet carrier
A rescue centre in Cambridgeshire took in 11 abandoned animals in the first four days of 2010, the RSPCA said.
Block Fen Animal Centre in Wimblington, near March, took in a cockerel and two puppies on Saturday.
Two litters of kittens were found in Norfolk on Monday. All animals were left in boxes and were freezing cold.
Centre manager Jackie Williams said: "This is one of the busiest starts to a new year we've had in terms of abandoned animals."
The cross-breed cockerel, which was in a cardboard pet carrier, was left outside Block Fen on Saturday morning.
The RSCPA said he was about six months old and was skinny and very cold but is now recovering well. Staff have named him Harold and he is living in an enclosure with a hen named Mary who was already being cared for at the centre.
The two lurcher terrier cross puppies are believed to be seven to eight weeks old and were found dumped in a wicker laundry basket in the front garden of a house in The Causeway in March.
Their whimpers were heard and a member of the public took them to Block Fen, where they have been named Oliver and Dodger. They are being treated for severe diarrhoea.
Four nine-week-old kittens were found in a cardboard box in Morrison's car park in King's Lynn in Norfolk and came in to Block Fen on Monday morning.
A black six-month-old female cat was also with them but is not thought to be their mother.
A note had been attached to the box which read: "Please find me good homes."
The second litter of three four-month-old kittens was found in a plastic cat carrier in The Cottons in Outwell, Norfolk.
Ms Williams added: "It is so uncaring to leave young animals like these outside in freezing temperatures.
"It's only by luck that they did not suffer worse fates. It is about time that people took responsibility for their pets - simply dumping them and hoping someone else will step in is not enough."
The RSPCA said the animals are not yet ready for new homes, but Block Fen has lots of animals which are "desperate" for new owners.