The addition of fowlpox and pigeon pox vaccine to Marek's vaccine for broilers.

Laboratory and field studies indicated that a cell-culture fowlpox vaccine was effective and safe when administered subcutaneously to day-old broiler chicks in combination with cell-associated Marek's vaccine without compromising the latter. Pox vaccines of chick embryo origin evaluated similarly provided excellent protection, although they caused local musculature swelling when injected into muscle rather than under the skin. No muscle swelling followed improper vaccination with the cell-culture fowlpox vaccine.