Ocenę wylęgowości przeprowadzono na 133 jajach strusich, które w zależności od masy podzielono na 3 grupy: I – jaja o masie od 1300 do 1450 g, II – jaja o masie od 1451 do 1600 g, III – jaja o masie od 1601 do 1750 g. Największy odsetek zarodków zamarłych (30%) stwierdzono w grupie I, natomiast w pozostałych dwóch wskaźnik ten był mniejszy, odpowiednio o 22,6 i 12,4%. Najwyższe wskaźniki wylęgowości zarówno z jaj nałożonych, jak i zapłodnionych stwierdzono w grupie II, odpowiednio 66,6 i 88,8%. Optimum masy strusich jaj wylęgowych winno mieścić się w przedziale 1451–1600 g.
The aim of the study was to determine a reason for failing health condition and deaths amang the ostriches in the newly-established breeding farm situated within the boundaries of Toruń Voivodship. Both initial observations and examinations of three alive and two dead birds presupposed an appearance of ectoparasitical disease. The autopsies were performed and the specimens for bacteriological and perasitological studies were subsequently obtained. The ectoparasitically-directed studies were the only positive result; the individuals of Cnemidocoptes mutans and unrecognised Acarina species were found. Although the overall treatment (Ivomec) and breeding-rooms extennination of vermin (Neguvon 2%) were held, health conditions of the ostriches failed to improve and, as a result, all the birds died. The breeding farm was closed down wich the owner having suffered financially. The study allowed to draw conclusions concerning reasons for Acarina invasion and subsequent deaths among the birds.