What are the costs and profits of Rex rabbit farming?

The American Rex rabbit is a valuable fur animal introduced from the United States. Its main purpose is fur, as it is a high-grade leather material. Its meat is rich in nutrients. Raising Rex rabbits is an emerging high-efficiency industry. They breed quickly; a single doe can average five to six litters per year, with an average of 6 surviving per litter. For each group (1 male and 3 females), calculated at 5 litters, 90 commercial Rex rabbits (5.0 jin and above) can be marketed per year (that is, 6×5×3=90). Note: the following data are all theoretical and may differ from actual farming costs.
Breeding rabbit costs
1. Feed cost: each rabbit requires about 70 jin of mixed concentrate per year. Calculated at 0.7 yuan per jin, each rabbit needs 49 yuan per year, and one group needs 49×4=196 yuan.
2. Epidemic prevention and medicine costs: 2 yuan per rabbit, so one group is 2×4=8 yuan.
3. Depreciation and allocation cost of breeding rabbits: calculated on a three-year use basis. If one group of rabbits is counted at 600 yuan, after three years they can be culled and 50 yuan×4=200 yuan recovered. The actual loss is 600-200=500 yuan, then divided by 3 (years), that is, 166 yuan allocated per year.
4. Total cost: 196 + 8 + 166 = 362 yuan.
Commercial rabbit costs
Raising each commercial rabbit to over 5.0 jin requires 25 jin of concentrate (about 150 days). Calculated at 0.7 yuan per jin, that is 0.7×25=17.5 yuan; epidemic prevention and medicine costs are 1 yuan per rabbit; the subtotal is 18.5 yuan per rabbit. Each group of 3 (female rabbits) × 30 (number bred per female rabbit) × 18.5 yuan (cost per rabbit) = 90 rabbits × 18.5 yuan = 1665 yuan.
Profit per group
1. Gross profit: calculated at the average price of recent years, that is, live rabbits of 5.0 jin and above are about 6-10 yuan per jin. Selling 30 per year, with each rabbit weighed at 5.0 jin and an average of 8 yuan per jin, that is 30 rabbits × 5.0 jin × 3 (female rabbits per group) × 8 yuan = 3600 yuan
2. Net profit: gross profit - breeding rabbit cost - commercial rabbit cost, that is: 3600 yuan - 362 yuan - 1665 yuan = 1573 yuan.