Problem firstley the r com is not suitabul for call or peakin duck ,yes they will hatch some but not meney, the old man asked me to have a go last yare att some calls very hard .we have a r com i tried 3 incubaters they are hard to hatch the brinsea still air was best no fan and water filled from day 1 very cheap to pic up .iff you got 10 you would be doin well. Think off this 1950 to late 60s there was onley parrafin incubaters and 70 percent hatch? Naw we have all the kit but that dosent garantey that itt is better .iv used them all i have a marcelis the best on the market steve next doore has a wine fridge from the tip home made naw his cost 70 pounds mine over 1000 same lot off eggs, we put in a full lot off eggs from my stock he had 70 percent hatch i had 76 .so meney things to get right temp some hatch dry etc.