I am using the card Blood Bairn, which has the following activated ability:
Sacrifice another creature: Blood Bairn gets +2/+2 until end of turn.
I use my Blood Bairn in conjunction with Festering Newts, which allow me to give a target creature -1/-1 when it dies. The sacrifice allows it to die and lets me hurt a creature. If I have, say, 2 Festering Newts on the field, can I activate Blood Bairn's ability with both Festering Newts, allowing me to not only give -1/-1 to 2 target creatures but also giving Blood Bairn +4/+4?