Don't think you want the hair and all that would be washed off(bedding, leaves ect...) going in there and messing up the works.
Best to keep mother and the kids happy, so you get to keep the hounds ...Patch
I have been using a 1000 gallon septic tank system for my kennels for years. I works great and has never given me any problems. I don't have to shovel dog waste every day. Just spray it down into a concrete trough that leads to the septic tank.
I add a bottle of Roebic 37 or an equivalent to the septic tank twice a year to help break down the waste. I've been using the septic tank system for at least ten years and have never had a problem. The main thing is to make sure the septic system has a good drain field and don't wash bedding material such as straw or cedar chips into the system. I don't use any bedding material for the dogs. I use heat lamps in the houses and they are controlled by a commercial thermostat to turn on and off according to the outside temperature. I ran all wiring in EMT conduit to keep the dogs from chewing it. Hope this helps you.