Metzorah - Shlishi
That's a Lot of Sheep
Three sheep can be pretty pricey and not every metzora can afford that. If it's beyond the person's means, he can just bring one male sheep as the asham (guilt offering) and the flour. In such a case, he should replace the other two sheep with bird sacrifices for the chatas and olah (sin offering and burnt offering, respectively).
The process is identical to when three sheep are used: offer the asham, place the blood on the ear, thumb and toe, oil, then the chatas and the olah (in this case birds) and, finally, the mincha. All done.