pubmed-article:8062114 | pubmed:abstractText | 1. Heterophils (H) and lymphocytes (L) were measured in embryos that had pipped into the air cell and through the shell, and in chicks from 0-d-old to 8 d of age. 2. Numbers of lymphocytes in the perinatal stages were very low with H:L ratios greater than 5.0. 3. Posthatching H:L ratios decreased in a quadratic manner from 1.76 at hatch to 0.39 on day 8. | lld:pubmed |