We've been running these for 40 chickens since 2018. Birds are locked in the coop at night but free range one acre during the day. One nipple fount is in the coop, and a big open pail of water is outside. Together, that's plenty of water for 40 birds. When it freezes hard, our birds stay in the coop all day. They drink over a gallon a day, so we have to refill the fount every 2 days. It's worth noting that as the water level goes down, flow from the water nipples is reduced. So although it's a 5 gallon fount, we always refill at half full.
We have an entire spare fount on hand, just in case the one in the coop breaks. It's plastic, which gets brittle when frozen, so when it's cold we don't open it, we use the fill plug on top.
If you buy new one from Rentacoop, those fill plugs cost $3 each - ouch - and they will break again after a couple years.
In fact, all their replacement parts seem expensive to me. Perhaps they are not made in China. I don't know. You could adapt something else, or whittle a wood plug. $3 for a silly little plastic plug that lasts 2 years is a bit much.
Our founts don't leak much. We agitate the metal part to clear the nipples. If you let crud buildup in your water, that would probably gunk up the nipples and make them leak a lot. But your chickens need clean water anyway, so clean the bucket every week or so, depending on algae buildup. If dirt is getting in there, you're doing something wrong. Keep it clean.
We also put Oxyne in the water, diluted to .09 %, for overall chicken health. This has reduced chicken respiratory illness substantially for us. The Oxyne has the side benefit of reducing algae buildup in the fount during warm months.
I would not place this fount in direct sun. We live in Texas and the strong sun kills plastic. Keep it in the shade.
Our fount came with an anti-roosting cap on top. Rentacoop also included two extra nipples. They should also include extra fill plugs, given that they get brittle in 2 years and begin to crack up.