Madonna has upset animal activists by dyeing her sheep blue, pink, yellow and green for a Vogue spread at her English country estate, music-news.com reports.
Madonna, 49, and her husband Guy Ritchie, 39, insisted the dye used was temporary and did not harm the animals, the Web site reported.
But the Royal Society for the Prevention of Cruelty to Animals stated that even though the dye may be safe for the animals, those who copy this stunt might not be so careful.
"Why is it necessary and what are they trying to prove? It is an irresponsible publicity stunt. It sends out the wrong message about how to use animals," an RSPCA spokesperson told the Web site.
The couple says the shoot was staged in homage to legendary photographer Cecil Beaton. The noted portrait photographer lived on the Ashcombe Estate during the '30s and '40s.
The shoot was for the book "Vogue Living: Houses, Gardens, People," in which Madonna is one of 36 profiled celebrities.