Yeshivat Kissei Rachamim head Rabbi Meir Mazuz made clear during his weekly lesson that it is preferable to observe the Kapparotcustom with money rather than chickens.
Kapparot involves gently passing a live chicken over one’s head three times and reciting the relevant prayer containing a request that the bird be expiation for the errant individual, that the chicken will die while the person will continue on to good life. After slaughtering the chicken is donated to the poor. There are also those who perform kapparot with fish.
"Once I used to use chickens, but it caused a mess in the house, because sometimes they make everything dirty and sometimes the chicken dies en route, and it's not simple. So I said we'd do the procedure to release us from continuing the custom, and we'd do kapparot with money. Money is better in every way; for one thing it's not dirty, nor is there the problem the Ben Ish Chai wrote that the chicken sees its friends being slaughtered, panics, and its lungs contract," he said, as reported by Kikar Hashabbat.
According to him, there is also concern of cruelty to animals. "They bring the chicken to the poor person, he says 'They already brought me a hundred chickens; where am I going to put all this? I don't have a big freezer. If I keep a little here and a little there, then I eat them on Sukkot and Hanukkah and Cheshvan and Tevet and Shevat, and I'll still have left for Purim...'
"That's joy for the poor man? And sometimes these birds sit in the car for hours in the heat of the sun, and that's animal cruelty."